Catalyst compositions and their use for hydrogenation of nitrile rubber

ABSTRACT

This invention relates to novel catalyst compositions based on ruthenium or osmium carbene-complex catalysts, pref. of the Grubbs-I, -II or -III type or fluorenylidene analogues thereof, and terminal olefins, pref. enol ethers such as ethyl vinyl ether (EVE or VEE) as co-catalysts and to a process for selectively hydrogenating nitrile rubbers in the presence of such catalyst compositions, pref. with a preceding metathesis step using the same complex catalyst as in the hydrogenation step.

FIELD OF THE INVENTION

This invention relates to novel catalyst compositions obtainable fromreacting Ruthenium- or Osmium-based complex catalysts with specificco-catalysts and to a process for selectively hydrogenating nitrilerubbers in the presence of such novel catalyst compositions.

BACKGROUND OF THE INVENTION

The term “acrylonitrile-butadiene rubber” or “nitrile rubber”, alsonamed as “NBR” for short, shall be interpreted broadly and refers torubbers which are copolymers or terpolymers of at least one α,β-unsaturated nitrile, at least one conjugated diene and, if desired,one or more further copolymerizable monomers.

Hydrogenated NBR, also referred to as “HNBR” for short, is producedcommercially by hydrogenation of NBR. Accordingly, the selectivehydrogenation of the carbon-carbon double bonds in the diene-basedpolymer must be conducted without affecting the nitrile groups and otherfunctional groups (such as carboxyl groups when other copolymerizablemonomers were introduced into the polymer chains) in the polymer chains.

HNBR is a specialty rubber which has very good heat resistance, anexcellent resistance to ozone and chemicals and also an excellent oilresistance. The abovementioned physical and chemical properties of HNBRare associated with very good mechanical properties, in particular ahigh abrasion resistance. For this reason, HNBR has found wide use in avariety of applications. HNBR is used, for example, for seals, hoses,belts and damping elements in the automobile sector, also for stators,oil well seals and valve seals in the field of oil exploration and alsofor numerous parts in the aircraft industry, the electronics industry,mechanical engineering and shipbuilding. A hydrogenation conversionhigher than 95%, or a residual double bond (RDB) content <5%, withoutcross-linking during the hydrogenation reaction and a gel level of lessthan about 2.5% in the resultant HNBR is a threshold that ensureshigh-performance applications of HNBR in these areas and guaranteesexcellent processability of the final product.

The degree of hydrogenation of the copolymerized diene units in HNBR mayvary in the range from 50 to 100%, however, the desired hydrogenationdegree is from about 80 to about 100%, preferably from about 90 to about99.9%. Commercial grades of HNBR typically have a remaining level ofunsaturation below 18% and a content of acrylonitrile of roughly up toabout 50%.

It is possible to carry out the hydrogenation of NBR either withhomogeneous or with heterogeneous hydrogenation catalysts. The catalystsused are usually based on rhodium, ruthenium or palladium, but it isalso possible to use platinum, iridium, rhenium, osmium, cobalt orcopper either as metal or preferably in the form of metal compounds (seee.g. U.S. Pat. No. 3,700,637, DE-A-25 39 132, EP-A-0 134 023, DE-A-35 41689, DE-A-35 40 918, EP-A-0 298 386, DE-A-35 29 252, DE-A-34 33 392,U.S. Pat. No. 4,464,515 and U.S. Pat. No. 4,503,196). Suitable catalystsand solvents for a hydrogenation in the homogeneous phase are known fromDE-A-25 39 132 and EP-A-0 471 250.

Also for commercial purposes the production of HNBR by hydrogenation ofNBR is performed in organic solvents by using either a heterogeneous ora homogeneous transition metal catalyst often based on rhodium orpalladium. Such processes suffer from drawbacks such as high prices forthe catalyst metals and the cost involved in catalyst metalremoval/recycle. This has led to research and development of alternativecatalysts based on cheaper noble metals, such as osmium and ruthenium.

Alternative NBR hydrogenation processes can be performed using Os-basedcatalysts. One catalyst excellently suited for NBR hydrogenation isOsHCl(CO)(O₂)(PCy₃)₂ as described in Ind. Eng. Chem. Res., 1998, 37(11),4253-4261. The rates of hydrogenation using this catalyst are superiorto those produced by Wilkinson's catalyst (RhCl(PPh₃)₃) over the entirerange of reaction conditions studied.

Ru-based complexes are also good catalysts for polymer solutionhydrogenation, and the price for Ru metal is even cheaper. Ru—PPh₃complexes and RuHCl(CO)L₂ (L is a bulky phosphine) catalyst systems leadto quantitative hydrogenation of NBR as disclosed in Journal ofMolecular Catalysis A: Chemical, 1997, 126(2-3), 115-131). During suchhydrogenation it is not necessary to add a free phosphine ligand tomaintain the catalyst activity. However, they are prone to gel formationand may cause a certain degree of cross-linking during hydrogenation.

However, these above mentioned Os or Ru catalysts are active catalystsfor hydrogenation only, not for metathesis reactions. Therefore, thesetypes of Os or Ru catalysts cannot be used for NBRmetathesis/degradation to produce NBR with reduced molecular weight.

Another problem of the HNBR production is that HNBR with a low Mooneyviscosity is difficult to manufacture by the direct hydrogenation ofcommercially available NBR. The relatively high Mooney viscosity placesrestrictions on the processability of HNBR. Many applications wouldideally use HNBR grades with a lower molecular weight and a lower Mooneyviscosity. This would give a decisive improvement in processability.

For a long time, it has not been possible to produce HNBR on a largescale having a low molar mass corresponding to a Mooney viscosity (ML1+4at 100° C.) in the range below 55 or with a weight average molecularweight of about Mw<200000 g/mol by means of the established direct NBRhydrogenation processes mainly for two reasons: Firstly a sharp increasein the Mooney viscosity occurs during hydrogenation of NBR which meansthat a HNBR polymer with substantially increased Mooney viscosity isobtained. The Mooney Increase Ratio (MIR) is generally around 2 or evenabove, depending upon the NBR grade, hydrogenation level and nature ofthe NBR feedstock. Thus, the Mooney viscosity range of marketed HNBR islimited by the lower limit of the Mooney viscosity of the NBR startingmaterial. Secondly, the molar mass of the NBR feedstock to be used forthe hydrogenation cannot be reduced at will since otherwise work-up inthe NBR industrial plants available is no longer possible because therubber becomes too sticky. The lowest Mooney viscosity of an NBRfeedstock which can be worked up without difficulties in an establishedindustrial plant is in a range of about 30 Mooney units (ML1+4 at 100°C.). The Mooney viscosity of the hydrogenated nitrile rubber obtainedusing such an NBR feedstock is in the order of 55 Mooney units (ML1+4 at100° C.). The Mooney viscosity is determined in accordance with ASTMstandard D 1646.

In the more recent prior art, this problem is solved by reducing themolecular weight of the nitrile rubber before hydrogenation bydegradation to a Mooney viscosity (ML1+4 at 100° C.) of less than 30Mooney units or a weight average molecular weight of Mw<200000 g/mol.The reduction in the molecular weight is achieved by metathesis of theNBR in the presence of metathesis catalysts. WO-A-02/100905 andWO-A-02/100941 describe for example a process which comprisesdegradation of nitrile rubber starting polymers by olefin metathesis andsubsequent hydrogenation. A nitrile rubber is reacted in a first step inthe presence of a coolefine and a specific catalyst based on osmium,ruthenium, molybdenum or tungsten complexes and hydrogenated in a secondstep. The hydrogenated nitrile rubbers obtained may have a weightaverage molecular weight (Mw) in the range from 30 000 to 250 000, aMooney viscosity (ML 1+4 at 100° C.) in the range from 3 to 50 and apolydispersity index PDI of less than 2.5. The metathesis reaction isadvantageously carried out in the same solvent as the subsequenthydrogenation so that the degraded nitrile rubber does not have to benecessarily isolated from the solvent after the degradation reaction iscomplete. Well-known for metathesis of nitrile rubber are a number ofRu-based metathesis catalysts like e.g. Grubbs I (benzylidenebis(tricyclohexylphosphine)dichloro ruthenium), Grubbs II (benzylidene[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinyliden]tricyclohexylphosphindichloro ruthenium), Grubbs III(benzylidene[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro-bis(3-bromopyridine)ruthenium),Hoveyda-Grubbs II([1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinyliden]dichloro(o-isopropoxyphenylmethylen)ruthenium) (see e.g. US-A-2008/0064882) and a number offluorenyliden-based complex catalysts (see e.g. US-A-2009/0076226)

EP-A-1 905 777 discloses ruthenium complex catalysts having the generalstructure

wherein

-   M is ruthenium,-   X¹ and X² are each chloro or RCOO with R in such RCOO being C₁-C₂₀    alkyl or a derivative thereof,-   L is an electron donating complex ligand, which could be linked or    not linked with X¹ to form a cyclic structure-   Y is oxygen, sulfur, nitrogen or phosphorus;-   R is H, halogen atom, nitro, cyano, C₁-C₂₀ alkyl, C₁-C₂₀ alkoxy,    C₁-C₂₀ alkylthio, C₁-C₂₀ silanyl, C₁-C₂₀ silanyloxy, C₆-C₂₀ aryl,    C₆-C₂₀ aryloxy, C₂-C₂₀ heterocyclic, C₂-C₂₀ heterocyclic aryl,    sulfinyl, sulfonyl, formyl, C₁-C₂₀ carbonyl, C₁-C₂₀ ester, C₁-C₂₀    amido, C₁-C₂₀ uramido or derivatives or C₁-C₂₀ sulfonamido group;-   R¹ and R² are each H, bromo (Br), iodo (I), C₁-C₂₀ alkyl or    derivatives, C₁-C₂₀ alkoxy, C₁-C₂₀ alkylthio, C₁-C₂₀ silanyloxy,    C₆-C₂₀ aryloxy, C₆-C₂₀ aryl, C₂-C₂₀ heterocyclic, C₂-C₂₀    heterocyclic aryl, C₁-C₂₀ ester, C₁-C₂₀ amido, C₁-C₂₀ uramido or    derivatives or C₁-C₂₀ sulfonamido group;-   R³ is H, C₁-C₂₀ alkyl or derivatives, C₁-C₂₀ alkoxy, C₁-C₂₀    alkylthio, C₁-C₂₀ silanyl, C₁-C₂₀ silanyloxy, C₆-C₂₀ aryl, C₆-C₂₀    aryloxy. C₂-C₂₀ heterocyclic, C₂-C₂₀ heterocyclic aryl, sulfinyl,    sulfonyl, C₁-C₂₀ carbonyl, C₁-C₂₀ ester, C₁-C₂₀ amido, C₁-C₂₀    uramido or derivatives or C₁-C₂₀ sulfonamido group; and-   EWG is C₁-C₂₀ aminosulfonyl (SO₂NR₂), formyl, C₁-C₂₀ carbonyl,    C₁-C₂₀ ester, C₁-C₂₀ aminocarbonyl (CONR₂), amido, chloro, fluoro,    C₁-C₂₀ uramido or derivatives or C₁-C₂₀ sulfonamido group.

EP-A-1 905 777 further states that these catalysts can be used in olefnmetathesis reactions including ring-closing olefin metathesis reactions,intermolecular olefin metathesis reactions, and olefin metathesispolymerization reactions. The examples show the preparation of lowmolecular weight substances by intramolecular ring closing metathesis inthe presence of certain of the generally disclosed catalysts. EP-A-1 905777 does neither provide any disclosure that these catalysts can be usedto degrade the molecular weight of polymers, in particular nitrilerubbers nor that they show any hydrogenation activity.

Furtheron processes for simultaneous metathesis and hydrogenation areknown from prior art. In WO-A-2005/080456 the preparation ofhydrogenated nitrile rubber polymers having low molecular weights andnarrower molecular weight distributions than those known in the art iscarried out by simultaneously subjecting the nitrile rubber to ametathesis reaction and a hydrogenation reaction. The reaction takesplace in the presence of a Ruthenium- or Osmium-based pentacoordinatedcomplex catalyst, in particular1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)(tricyclohexylphosphine) ruthenium (phenylmethy-lene)dichloride (alsocalled Grubbs 2^(nd) generation catalyst). However, WO-A-2005/080456does not provide any disclosure or teaching how to influence the twosimultaneously occurring reactions, i.e. metathesis and hydrogenation orhow to control the activity of the respective catalysts regardingmetathesis and hydrogenation.

WO-A-2011/023788 also discloses a process for subjecting a nitrilerubber in the presence of hydrogen to a combined and simultaneousmetathesis and hydrogenation reaction in the presence of specificallydefined hexacoordinated Ruthenium-oder Osmium based catalysts in orderto prepare hydrogenated nitrile rubbers having lower molecular weightsand narrower molecular weight distributions than those known in the art.Such process is performed by using at least one catalyst of generalformula (I) to (III)

where

-   M is ruthenium or osmium,-   X¹ and X² are identical or different ligands, preferably anionic    ligands,-   Z¹ and Z² are identical or different and neutral electron donor    ligands,-   R³ and R⁴ are each independently H or a substituent selected from    the group consisting of alkyl, cycloalkyl, alkenyl, alkynyl, aryl,    carboxylate, alkoxy, alkenyloxy, alkynyl-oxy, aryloxy,    alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl and    alkylsulphinyl radical, each of which may optionally be substituted    by one or more alkyl, halogen, alkoxy, aryl or heteroaryl moities,    and-   L is a ligand.

WO-A-2011/029732 also discloses an alternative process for subjecting anitrile rubber in the presence of hydrogen to a combined andsimultaneous metathesis and hydrogenation reaction in the presence ofspecifically defined pentacoordinated Ruthenium- or Osmium basedcatalysts in order to prepare hydrogenated nitrile rubbers having lowmolecular weights and a narrow molecular weight distribution. Suchprocess is performed in the presence of at least one compound of thegeneral formula (I),

where

-   M is ruthenium or osmium,-   Y is oxygen (O), sulphur (S), an N—R¹ radical or a P—R¹ radical,-   X¹ and X² are identical or different ligands,-   R¹ is an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy,    alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino,    alkylthio, arylthio, alkylsulphonyl, CR¹³C(O)R¹⁴ or alkylsulphinyl    moiety, each of which may optionally be substituted by one or more    alkyl, halogen, alkoxy, aryl or heteroaryl moiety,-   R¹³ is hydrogen or alkyl, cycloalkyl, alkenyl, alkynyl, aryl,    alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino,    alkylthio, arylthio, alkylsulphonyl or alkylsulphinyl moiety, each    of which may optionally be substituted by one or more alkyl,    halogen, alkoxy, aryl or heteroaryl moiety;-   R¹⁴ is alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy,    alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino,    alkylthio, arylthio, alkylsulphonyl or alkylsulphinyl moiety, each    of which may optionally be substituted by one or more alkyl,    halogen, alkoxy, aryl or heteroaryl moiety;-   R², R³, R⁴ and R⁵ are identical or different and are each H, organic    or inorganic radicals,-   R⁶ is H or an alkyl, alkenyl, alkynyl or aryl radical and-   L is a ligand.

However, neither WO-A-2011/023788 nor WO-A-2011/029732 provide anydisclosure or teaching how to influence the two simultaneously occurringreactions, i.e. metathesis and hydrogenation or how to control thetwo-fold activity of the respective catalysts for metathesis andhydrogenation.

WO-A-2011/079799 discloses a broad variety of catalysts the generalstructure of which is shown hereinafter

It is stated that such catalysts can be used to provide modified nitrilebutadiene rubber (NBR) or styrene-butadiene rubber (SBR) bydepolymerisation. It is further stated that the catalysts can be used ina method of making a depolymerized HNBR or styrene-butadiene rubber byadding one or more of those catalysts first to carry outdepolymerisation of NBR, followed by adding hydrogen into the reactorunder high pressure for hydrogenation. In another embodiment it isdisclosed to prepare HNBR by adding hydrogen under high pressure first,then followed by adding one or more of the above catalysts. However,WO-A-2011/079799 does not provide any disclosure or teaching how toinfluence the different catalytic activities of the catalysts fordepolymerisation (metathesis) and hydrogenation. It is accepted thatwhile hydrogenation takes place simultaneously metathesis leads to adegradation of the molecular weight in uncontrolled manner.

A number of references describe the use of metathesis catalysts in twostep reactions starting with a ring-opening metathesis polymerisation(ROMP) first which is followed by a hydrogenation reaction (so called“tandem polymerization/hydrogenation reactions”).

According to Organometallics, 2001, 20(26), 5495-5497 the metathesiscatalyst Grubbs I can be used for ROMP of cyclooctene or a norbornenederivative first, then followed by a hydrogenation of the polymers. Itis reported that the addition of a base like NEt₃ increases thecatalytic activity in the hydrogenation reaction.

J. Am. Chem. Soc 2007, 129, 4168-9 also relates to tandemROMP-hydrogenation reactions starting from functionalized norbornenesand compares the use of three Ruthenium-based catalysts, i.e. Grubbs I,Grubbs II and Grubbs III catalysts in such tandem reactions. It isdescribed that the Ruthenium-based catalyst on the end of the polymerbackbone is liberated and transformed into a hydrogenation-activespecies through reaction with H₂, base (NEt₃), and methanol.

EP-A-1 197 509 and JP 2005/272572A discloses a process for preparing ahydrogenated polymer by polymerizing a cycloolefine in the presence ofan organo ruthenium or osmium compound and subsequently subjecting theunsaturated polymer obtained during polymerization to a hydrogenationunder addition of a hydrogenation catalyst. EP-A-1 197 509 does notdescribe any cross-metathesis and does not relate to any degradation ofthe polymer via metathesis. JP 2005/272572 A discloses that thepolymerisation reaction catalyzed by the metathesis catalyst is stoppedby adding alkyl vinyl ether to the reaction system. Thereafter thehydrogenation reaction is performed without adding any further ordifferent catalyst. In Example 1 of JP 2005/272572A Grubbs II catalystis used in an amount of 0.05 parts by weight and 0.03 parts by weight ofethyl vinyl ether are added after the polymerisation reaction, hence themolar ratio of metathesis catalyst to ethyl vinyl ether is 1:7. In thedescription of JP 2005/272572A it is further disclosed that the molarratio of metathesis catalyst to alkyl vinyl ether is generally 1:1 to1:100, preferably 1:1 to 1:10.

Inorg. Chem 2000, 39, 5412-14 also explores tandem ROMPpolymerization/hydrogenation reactions. The focus lies on the mechanismof the hydrogenolysis of the ruthenium-based metathesis catalyst GrubbsI. It is shown that such catalyst is transformed into dihydride,dihydrogen and hydride species under conditions relevant tohydrogenation chemistry. However, there is no disclosure at all aboutpolymer degradation via metathesis or hydrogenation of unsaturatedpolymers.

In further references the quenching of metathesis reactions with vinylcompounds is described: Numerous patent applications, e.g.US-A-2007/0049700, US-A-2008/0064882, US-A-2007/0208206,US-A-2008/0076881, US-A-2009/054597, US-A-2009/0069516,US-A-2009/0076227, US-A-2009/0076226, US-A-2010/0087600, andUS-A-2010/0093944, and two not yet published patent applications withthe serial numbers EP 11153437.6 and PCT/EP2011/063570 are referring tothe molecular weight degradation of nitrile rubbers by a methathesisreaction and contain experiments in which the reaction mixture istreated with vinylethylether after the metathesis reaction in order todestroy the metathesis catalyst. The molar ratio of vinylethylether tothe metathesis catalysts used is very high in order to efficiently stopthe metathesis reaction by deactivation of the catalyst. In theaforementioned applications such molar ratio lies in a range of from567:1 to more than 17.000:1. None of those patent applications providesany disclosure or hint that by choosing lower ratios of the deactivatingreagent to the metathesis catalyst a catalyst composition is obtainedwhich is excellently suited for a selective hydrogenation, i.e. withoutcontinuing to catalyse the metathetic degradation.

In J. Am. Chem. Soc. 2001, 123, 6543-54 the mechanism of ruthenium basedcatalysts for olefin metathesis is disclosed. Furtheron it is describedthat the reaction of ruthenium carbenes with ethylvinylether can beutilized as a method for quenching ring opening metathesispolymerization. As shown in the following scheme a so-calledFischer-carbene complex is reported to be built.

In Tetrahedron Letters 50 (2009), 6103-5 it is disclosed that di(ethylene glycol) vinyl ether and amine derivatives thereof can also beused as deactivating reagents for olefin metathesis catalysts. It isexperimentally shown that the use of 4 equivalents of di (ethyleneglycol) vinyl ether based on the metathesis catalyst are sufficient toefficiently deactivate the metathesis catalyst. Even 2 equivalents arereported to be sufficient. However, this reference does not deal withhydrogenation processes subsequently to olefin metathesis at all.

In Macromol. Symp. 2010, 297, 25-32 it is shown that polyisobutylene(“PIB”) terminally functionalized with a vinyl ether group may serve tosequester a complex catalyst by conversion of a reactive rutheniumalkylidene complex into a phase-immobilized Fischer carbene complex.Additionally kinetic studies are presented on the reaction of 2equivalents PIB vinyl ether and 6 as well as 15 equivalents of ethylvinyl ether with Grubbs II catalyst.

It can be seen from the above that:

-   (1) up to now, hydrogenation catalysts which are very active for the    selective hydrogenation of nitrile rubbers are known and Rh- and    Pd-based catalysts are already used in industrial hydrogenation    processes; however, cheaper Ru-based hydrogenation catalysts are    still facing the gel formation problem when used for NBR    hydrogenation. Most importantly, only HNBR with high molecular    weight can be produced by using these catalysts which can only    catalyse the NBR hydrogenation. The molecular weight of the final    HNBR is determined by the molecular weight of the raw NBR, not by    the hydrogenation catalysts;-   (2) the degradation of nitrile rubber by metathesis is known using    ruthenium- or osmium-based metathesis catalysts followed by a    hydrogenation of the degraded nitrile rubber to afford hydrogenated    nitrile rubber; if the same catalyst is used for metathesis and for    hydrogenation, such catalysts are highly active for NBR metathesis    while not so active for NBR hydrogenation; and-   (3) catalysts which possess both, i.e. catalytic activity for both,    metathesis and hydrogenation, cannot be used in a controlled manner

Therefore, in current commercial production processes, a separatehydrogenation catalyst is added into the reaction system for the NBRhydrogenation after the NBR metathesis step. In this way, HNBR withcontrolled molecular weight can be produced, but two catalysts (one formetathesis and one for hydrogenation) are required to achieve highreaction efficiency.

However, hitherto there is not a single literature reporting thepreparation of hydrogenated nitrile rubber with controlled molecularweight and therefore controllable Mooney viscosity only using one kindof ruthenium- or osmium-based catalyst which is otherwise known for itsmetathetic activity. Also, up to now, there is no hydrogenation catalystwhich can be used at a very low concentration for NBR hydrogenation tohigh conversion. So far the catalyst removal or recycle step is requiredafter the hydrogenation.

Accordingly it was the object of the present invention to provide animproved catalyst composition allowing a selective hydrogenation ofnitrile rubber at low catalyst concentrations and short hydrogenationtimes. Additionally such improved catalyst composition should bedesigned in a way to allow an upstream metathesis reaction, if desired,using the same catalyst as contained in the catalyst composition.

SUMMARY OF THE INVENTION

The present invention relates to novel catalyst compositions which areobtainable by contacting a complex catalyst based on ruthenium or osmiumas central metal and bearing at least one ligand which is bound to theruthenium or osmium central metal in a carbene-like fashion with atleast one co-catalyst in a molar ratio of the complex catalyst to theco-catalyst in a range of from 1:(20-550) wherein the co-catalyst mustcontain at least one vinyl group.

In a particular embodiment the invention relates to novel catalystcompositions which are obtainable by contacting a complex catalyst basedon ruthenium or osmium as central metal and bearing at least one ligandwhich is bound to the ruthenium or osmium central metal in acarbene-like fashion with at least one co-catalyst must contain at leastone vinyl group and wherein the molar ratio of the complex catalyst tothe co-catalyst lies in a range of from 1:(20 to below 100), preferably1:(25 to 99.5), more preferably 1:(30 to 99), even more preferably 1:(35to 98.5), and most preferably 1:(40 to 70).

The invention furtheron relates to a process of hydrogenating a nitrilerubber comprising

-   a) preparing the catalyst composition according to the invention by    contacting a complex catalyst based on ruthenium or osmium as    central metal and bearing at least one ligand which is bound to the    ruthenium or osmium central metal in a carbene-like fashion with at    least one co-catalyst in a molar ratio of the complex catalyst to    the co-catalyst in the range of 1:(20-550) wherein the co-catalyst    must contain at least one vinyl group and thereafter-   b) hydrogenating the nitrile rubber in the presence of the novel    catalyst composition.

A specific embodiment of the present invention relates to an alternativeprocess which comprises firstly subjecting a nitrile rubber to amolecular weight degradation in a metathesis reaction by contacting thenitrile rubber in the absence or presence of a co-olefin with a complexcatalyst based on ruthenium or osmium as central metal and bearing atleast one ligand which is bound to the ruthenium or osmium central metaltransition metal in a carbene-like fashion, then

-   a) preparing the catalyst composition according to the invention by    contacting the complex catalyst which is present in the reaction    mixture after the metathesis reaction with at least one co-catalyst    in a molar ratio of the complex catalyst to the co-catalyst in the    range of 1:(20-550) wherein the co-catalyst must contain at least    one vinyl group and thereafter-   b) hydrogenating the nitrile rubber in the presence of the novel    catalyst composition.

In a particular embodiment the invention relates to the above processeswherein the molar ratio of the metathesis catalyst to the co-catalystlies in a range of from 1:(20 to below 100), preferably 1:(25 to 99.5),more preferably 1:(30 to 99), even more preferably 1:(35 to 98.5), andmost preferably 1:(40:70).

While the above described prior art like e.g. WO-A-2011/023788 andWO-A-2011/029732 always disclosed simultaneous and competing metathesiswhen a catalyst with metathesis activity was used for hydrogenation ofnitrile rubbers, the novel process advantageously allows for the firsttime to perform a hydrogenation of nitrile rubber without a simultaneousmetathetic degradation of the nitrile rubber, if a catalyst compositionis used which has been obtained by treating the metathesis catalyst witha vinyl compound first. Hence, the present process allows ahydrogenation of nitrile rubbers in a controlled manner, i.e. underformation of hydrogenated nitrile rubber with a tailormade molecularweight in a commercially attractive fashion. It is possible to keep themolecular weight of the nitrile rubber constant during hydrogenation. Inthe alternative it is also possible to adjust and regulate the molecularweight of the nitrile rubber in a desired manner by controlling andchoosing the molar ratio between the metathesis catalyst and theco-catalyst when preparing the novel catalyst composition. In particularthe present process allows in a specific embodiment to take advantage ofusing one and the same catalyst for a metathesis reaction in a firststep, then adding the co-catalyst to the reaction mixture of themetathesis reaction, thereby preparing the novel catalyst compositionand thereafter hydrogenating the metathesized nitrile rubber in a secondstep. The co-catalyst can be added at any degree of metathesis to thereaction mixture containing the transition-metal based metathesiscatalyst and therefore allows to prepare tailor-made hydrogenatednitrile rubbers in a commercially attractive fashion. Additionally thehydrogenation process of the present invention allows to use theruthenium- or osmium-based based catalyst in a very low concentration,so that there is no need to remove or recycle the transition metal basedcatalyst after the hydrogenation.

The catalyst composition prepared and used according to the presentinvention is characterized by its high hydrogenation activity. Highhydrogenation degrees may be achieved in short reaction times. Inparticular the hydrogenation activity of the novel catalyst compositionis higher than the hydrogenation activity of the correspondingruthenium- or osmium-based catalyst only used as such for NBRhydrogenation

DETAILED DESCRIPTION OF THE INVENTION

The term “substituted” used for the purposes of the present patentapplication means that a hydrogen atom on an indicated radical or atomhas been replaced by one of the groups indicated in each case, with theproviso that the valency of the atom indicated is not exceeded and thesubstitution leads to a stable compound.

For the purposes of the present patent application and invention, allthe definitions of moities, parameters or explanations given above orbelow in general terms or in preferred ranges can be combined with oneanother in any way, i.e. including combinations of the respective rangesand preferred ranges.

Co-Catalyst:

In a preferred embodiment the co-catalyst has the general formula (1)

CH₂═CRR′  (1)

in which R and R′ are identical or different and shall mean hydrogen,

-   OR¹ wherein R¹ shall mean alkyl, cycloalkyl, alkenyl, alkynyl, aryl,    or heteroaryl, C(═O)(R²), —C(═O)N(R²)₂, —[(CH₂)_(n)—X]_(m)R²,    —[(CH₂)_(n)—X]_(m)—CH═CH₂, or —(CH₂)_(p)—C(R³)₂R⁴    -   wherein    -   X is identical or different and means oxygen (O) or NR²    -   R² are identical or different and represent H, alkyl,        cycloalkyl, alkenyl, alkynyl, aryl, or heteroaryl,    -   R³ are identical or different and represent C₁-C₅ alkyl or        —(CH₂)_(n)—O—CH═CH₂,    -   R⁴ represents (CH₂)_(p)—O—CH═CH₂,    -   n is in the range of from 1 to 5,    -   m is in the range of from 1 to 10,    -   p is in the range of from 0 to 5,    -   or where in the alternative, if R and R′ both represent a group        OR¹, both R¹ may be linked to each other and together represent        a divalent group —(C(R²)₂)_(q)— with q being 2, 3 or 4 and    -   R² being identical or different and having the above defined        meanings,-   SR⁵, SOR⁵, SO₂R⁵    -   wherein R⁵ represents alkyl, cycloalkyl, alkenyl, alkynyl, aryl,        or heteroaryl,-   N(R⁶R⁷), P(R⁶R⁷)    -   wherein R⁶ and R⁷ are identical or different and shall mean        alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl,        —C(═O)(R²), or    -   where in the alternative R⁶ and R⁷ may form together with such N        or P atom to which they both are linked at the same time a        saturated, unsaturated or aromatic cyclic structure with 4 to 7        carbon atoms in the cyclic structure wherein one, two or three        of said carbon atoms can be replaced by a moiety selected from        oxygen, sulfur, nitrogen, N—R⁸ or P—R⁸ wherein R⁸ shall mean        alkyl, cycloalkyl, alkenyl, alkynyl, aryl, or heteroaryl, or-   P(═O)(OR⁹)₂    -   in which R⁹ are identical or different and shall mean alkyl,        cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl,-   however, under the proviso that R and R′ must not both represent    hydrogen at the same time.

In the co-catalysts according to general formula (1) all alkyl,cycloalkyl, alkenyl, alkynyl, aryl, or heteroaryl moieties in R¹, R²,R³, R⁴, R⁵, R⁶, R⁷, R⁸ or R⁹ may optionally be further substituted byone or more alkyl, halogen, alkoxy, alkenyloxy, aryl or heteroarylsubstituents. All aforementioned moities, in particular the alkyl,alkenyl and/or alkynyl moieties can be either straight chain or branchedto the extent chemically plausible. Of course, the above proviso thatthe valency of the atom indicated is not exceeded and the substitutionleads to a stable compound shall be fulfilled.

If R and R′ represent OR¹, both such R¹ can be linked to each other andtogether represent a divalent group —(C(R²)₂)_(q)— with q being 2, 3, 4or 5 and R² being identical or different and having the meanings definedregarding formula (1) above. In such case a cyclic structure is formedby the divalent group together with the two oxygen atoms to which it thedivalent group is bound and the adjacent vinylic carbon atom.

In another embodiment of the present invention the catalyst compositionis obtained using at least one, preferably one, co-catalyst having thegeneral formula (1)

CH₂═CRR′  (1)

in which R is hydrogen and R′ shall mean,

-   OR¹ wherein R¹ shall mean C₁-C₁₆-alkyl, C₃-C₁₀-cycloalkyl,    C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₆-C₂₄-heteroaryl,    —C(═O)(R²), —C(═O)N(R²)₂, —[(CH₂)_(n)X]_(m)R²,    —[(CH₂)_(n)X]_(m)—CH═CH₂, or —(CH₂)_(p)—C(R³)₂R⁴,    -   wherein    -   X is identical or different and oxygen (O) or NR²,    -   R² are identical or different and represent H, C₁-C₁₆-alkyl,        C₃-C₁₀-cycloalkyl, C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,        or C₃-C₂₀-heteroaryl,    -   R³ are identical or different and represent C₁-C₄ alkyl or        —(CH₂)_(n)—O—CH═CH₂,    -   R⁴ represents (CH₂)_(p)—O—CH═CH₂,    -   n is in the range of from 1 to 4,    -   m is in the range of from 1 to 5,    -   p is in the range of from 0 to 5,-   SR⁵, SOR⁵, SO₂R⁵    -   wherein R⁵ represents C₁-C₁₆-alkyl, C₃-C₁₀-cycloalkyl,        C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, or        C₆-C₂₄-heteroaryl,-   N(R⁶R⁷), P(R⁶R⁷)    -   wherein R⁶ and R⁷ are identical or different and shall mean        C₁-C₁₆-alkyl, C₃-C₁₀-cycloalkyl, C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl,        C₆-C₂₄-aryl, or C₆-C₂₄-heteroaryl, —C(═O)(R²), or where in the        alternative R⁶ and R⁷ may form together with such N or P atom to        which they both are linked at the same time a saturated,        unsaturated or aromatic cyclic structure with 4 to 7 carbon        atoms in the cyclic structure wherein one, two or three of said        carbon atoms can be replaced by a moiety selected from oxygen,        sulfur, nitrogen, N—R⁸ or P—R⁸ wherein R⁸ shall mean        C₁-C₁₆-alkyl, C₃-C₁₀-cycloalkyl, C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl,        C₆-C₂₄-aryl, or C₆-C₂₄-heteroaryl, or-   P(═O)(OR⁹)₂    -   in which R⁹ are identical or different and shall mean        C₁-C₁₆-alkyl, C₃-C₁₀-cycloalkyl, C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl,        C₆-C₂₄-aryl, or C₆-C₂₄-heteroaryl.

In another embodiment of the present invention the catalyst compositionis obtained using at least one, preferably one, co-catalyst having thegeneral formula (1)

CH₂═CRR′  (1)

-   in which R and R′ are identical or different and shall mean-   OR¹ wherein R¹ shall mean C₁-C₁₆-alkyl, C₃-C₁₀-cycloalkyl,    C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₆-C₂₄-heteroaryl,    —C(═O)(R²), —C(═O)N(R²)₂, —[(CH₂)_(n)X]_(m)R²,    —[(CH₂)_(n)X]_(m)—CH═CH₂, or —(CH₂)_(p)—C(R³)₂R⁴,    -   wherein    -   X is identical or different and oxygen (O) or NR²,    -   R² are identical or different and represent H, C₁-C₁₆-alkyl,        C₃-C₁₀-cycloalkyl, C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,        or C₃-C₂₀-heteroaryl,    -   R³ are identical or different and represent C₁-C₄ alkyl or        —(CH₂)_(n)—O—CH═CH₂,    -   R⁴ represents (CH₂)_(p)—O—CH═CH₂,    -   n is in the range of from 1 to 4,    -   m is in the range of from 1 to 5,    -   p is in the range of from 0 to 5,    -   or where in the alternative, if R and R′ both represent a group        OR¹, both R¹ may be linked to each other and together represent        a divalent group —(C(R²)₂)_(q)— with q being 2, 3 or 4 and    -   R² being identical or different and having the above defined        meanings,-   SR⁵, SOR⁵, SO₂R⁵    -   wherein R⁵ represents C₁-C₁₆-alkyl, C₃-C₁₀-cycloalkyl,        C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, or        C₆-C₂₄-heteroaryl,-   N(R⁶R⁷), P(R⁶R⁷)    -   wherein R⁶ and R⁷ are identical or different and shall mean        C₁-C₁₆-alkyl, C₃-C₁₀-cycloalkyl, C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl,        C₆-C₂₄-aryl, or C₆-C₂₄-heteroaryl, —C(═O)(R²), or where in the        alternative R⁶ and R⁷ may form together with such N or P atom to        which they both are linked at the same time a saturated,        unsaturated or aromatic cyclic structure with 4 to 7 carbon        atoms in the cyclic structure wherein one, two or three of said        carbon atoms can be replaced by a moiety selected from oxygen,        sulfur, nitrogen, N—R⁸ or P—R⁸ wherein R⁸ shall mean        C₁-C₁₆-alkyl, C₃-C₁₀-cycloalkyl, C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl,        C₆-C₂₄-aryl, or C₆-C₂₄-heteroaryl, or-   P(═O)(OR⁹)₂    -   in which R⁹ are identical or different and shall mean        C₁-C₁₆-alkyl, C₃-C₁₀-cycloalkyl, C₂-C₁₆-alkenyl, C₂-C₂₀-alkynyl,        C₆-C₂₄-aryl, or C₆-C₂₄-heteroaryl.

In another preferred embodiment of the present invention the catalystcomposition is obtained using at least one, preferably one, co-catalysthaving the above depicted general formula (1) wherein

CH₂═CRR′  (1)

-   in which R is hydrogen and R′ shall mean-   OR¹ wherein R¹ shall mean C₁-C₁₂-alkyl, C₅-C₈-cycloalkyl,    C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl, C₆-C₁₄-aryl, C₆-C₁₄-heteroaryl,    —C(═O)(R²), —C(═O)N(R²)₂, —[(CH₂)_(n)X]_(m)R²,    —[(CH₂)_(n)X]_(m)—CH═CH₂, or —(CH₂)_(p)—C(R³)₂R⁴,    -   wherein    -   X is identical or different and oxygen (O) or NR²,    -   R² are identical or different and represent H, C₁-C₁₂-alkyl,        C₅-C₈-cycloalkyl, C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl, C₆-C₁₄-aryl,        or C₃-C₁₄-heteroaryl, R³ are identical or different and        represent methyl, ethyl or —(CH₂)_(n)—O—CH═CH₂,    -   R⁴ represents (CH₂)_(p)—O—CH═CH₂,    -   n is 1, 2 or 3    -   m is 1, 2, 3, or 4,    -   p is 0, 1, 2, 3 or 4,-   SR⁵, SOR⁵, SO₂R⁵    -   wherein R⁵ represents C₁-C₁₂-alkyl, C₅-C₈-cycloalkyl,        C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl, C₆-C₁₄-aryl, or        C₃-C₁₄-heteroaryl,-   N(R⁶R⁷), P(R⁶R⁷)    -   wherein R⁶ and R⁷ are identical or different and shall mean        C₁-C₁₂-alkyl, C₅-C₈-cycloalkyl, C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl,        C₆-C₁₄-aryl, or C₆-C₁₄-heteroaryl, —C(═O)(R²), or where in the        alternative R⁶ and R⁷ may form together with such N or P atom to        which they both are linked at the same time a saturated,        unsaturated or aromatic cyclic structure with 4 to 5 carbon        atoms in the cyclic structure wherein one or two of said carbon        atoms can be replaced by a moiety selected from oxygen, sulfur,        nitrogen, N—R⁸ or P—R⁸ wherein R⁸ shall mean C₁-C₁₂-alkyl,        C₅-C₈-cycloalkyl, C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl, C₆-C₁₄-aryl,        or C₃-C₁₄-heteroaryl,-   P(═O)(OR⁹)₂    -   in which R⁹ are identical or different and shall mean        C₁-C₁₂-alkyl, C₅-C₈-cycloalkyl, C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl,        C₆-C₁₄-aryl, or C₆-C₁₄-heteroaryl.

In another preferred embodiment of the present invention the catalystcomposition is obtained using at least one, preferably one, co-catalysthaving the above depicted general formula (1) wherein

CH₂═CRR′  (1)

-   in which R and R′ are identical or different and shall mean-   OR¹ wherein R¹ shall mean C₁-C₁₂-alkyl, C₅-C₈-cycloalkyl,    C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl, C₆-C₁₄-aryl, C₆-C₁₄-heteroaryl,    —C(═O)(R²), —C(═O)N(R²)₂, —[(CH₂)_(n)X]_(m)R²,    —[(CH₂)_(n)X]_(m)—CH═CH₂, or —(CH₂)_(p)—C(R³)₂R⁴,    -   wherein    -   X is identical or different and oxygen (O) or NR²,    -   R² are identical or different and represent H, C₁-C₁₂-alkyl,        C₅-C₈-cycloalkyl, C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl, C₆-C₁₄-aryl,        or C₃-C₁₄-heteroaryl, R³ are identical or different and        represent methyl, ethyl or —(CH₂)_(n)—O—CH═CH₂,    -   R⁴ represents (CH₂)_(p)—O—CH═CH₂,    -   n is 1, 2 or 3    -   m is 1, 2, 3, or 4,    -   p is 0, 1, 2, 3 or 4,    -   or where in the alternative, if R and R′ both represent a group        OR¹, both R¹ may be linked to each other and together represent        a divalent group —(C(R²)₂)_(q)— with q being 2, or 3 and R²        being identical or different and representing hydrogen or C₁-C₄        alkyl,-   SR⁵, SOR⁵, SO₂R⁵    -   wherein R⁵ represents C₁-C₁₂-alkyl, C₅-C₈-cycloalkyl,        C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl, C₆-C₁₄-aryl, or        C₃-C₁₄-heteroaryl,-   N(R⁶R⁷), P(R⁶R⁷)    -   wherein R⁶ and R⁷ are identical or different and shall mean        C₁-C₁₂-alkyl, C₅-C₈-cycloalkyl, C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl,        C₆-C₁₄-aryl, or C₆-C₁₄-heteroaryl, —C(═O)(R²), or where in the        alternative R⁶ and R⁷ may form together with such N or P atom to        which they both are linked at the same time a saturated,        unsaturated or aromatic cyclic structure with 4 to 5 carbon        atoms in the cyclic structure wherein one or two of said carbon        atoms can be replaced by a moiety selected from oxygen, sulfur,        nitrogen, N—R⁸ or P—R⁸ wherein R⁸ shall mean C₁-C₁₂-alkyl,        C₅-C₈-cycloalkyl, C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl, C₆-C₁₄-aryl,        or C₃-C₁₄-heteroaryl,-   P(═O)(OR⁹)₂    -   in which R⁹ are identical or different and shall mean        C₁-C₁₂-alkyl, C₅-C₈-cycloalkyl, C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl,        C₆-C₁₄-aryl, or C₆-C₁₄-heteroaryl.

In another more preferred embodiment of the present invention thecatalyst composition is obtained using one co-catalyst having the abovedepicted general formulae (1) in which

-   R is hydrogen and R′ represents-   OR¹ wherein R¹ shall mean C₁-C₆-alkyl, C₅-C₆-cycloalkyl,    C₂-C₆-alkenyl, C₂-C₆-alkynyl, phenyl, imidazolyl, triazolyl, or    pyridinyl, —C(═O)(R²), —C(═O)N(R²)₂, —[(CH₂)_(n)O]_(m)R²,    —[(CH₂)_(n)O]_(m)—CH═CH₂, or —(CH₂)_(p)—C(R³)₂R⁴,    -   wherein    -   R² are identical or different and represent H, C₁-C₆-alkyl,        C₅-C₈-cycloalkyl, C₂-C₈-alkenyl, C₂-C₈-alkynyl, phenyl,        imidazolyl, triazolyl, or pyridinyl,    -   R³ are identical or different and represent methyl, ethyl or        —(CH₂)_(n)—O—CH═CH₂,    -   R⁴ represents (CH₂)_(p)—O—CH═CH₂,    -   n is 1, or 2,    -   m is 1, 2, or 3, and    -   p is 0, 1, or 3.

In all the above mentioned preferred, more preferred and most preferredembodiments of the co-catalysts according to general formula (1) thealkyl, cycloalkyl, alkenyl, alkynyl, aryl, or heteroaryl moieties in R¹,R², R³, R⁴, R⁵, R⁶, R⁷, R⁸ or R⁹ may optionally be further substitutedby one or more C₁-C₆-alkyl, C₅-C₆-cycloalkyl, C₂-C₆-alkenyl,C₂-C₆-alkynyl, phenyl, imidazolyl, triazolyl, or pyridinyl moieties. Allaforementioned substituents, in particular the alkyl, alkenyl and/oralkynyl moieties can be either straight chain or branched to the extentchemically plausible.

In an even more preferred embodiment of the present invention one ormore co-catalysts are used for the preparation of the novel catalystcompositions which have the following formulae:

In another also preferred embodiment of the present invention aco-catalyst is used for the preparation of the novel catalystcompositions in which R and R′ both represent OR¹ where such R¹ togetherform a divalent group as defined above, wherein such specificco-catalysts have the following formulae with R⁶ having the same meaningas outlined for general formula (1).

Catalysts:

The catalysts to be used in the process of the invention are complexcatalysts based either on ruthenium or osmium. Furtheron, these complexcatalysts have the common structural feature that they possess at leastone ligand which is bound to ruthenium or osmium in a carbene-likefashion. In a preferred embodiment, the complex catalyst has two carbeneligands, i.e. two ligands which are bound in a carbene-like fashion tothe central metal of the complex.

The novel catalyst composition of the present invention is obtainableusing for example a catalyst of the general formula (A),

where

-   M is osmium or ruthenium,-   X¹ and X² are identical or different and are two ligands, preferably    anionic ligands,-   L are identical or different ligands, preferably uncharged electron    donors,-   R are identical or different and are each hydrogen, alkyl,    preferably C₁-C₃₀-alkyl, cycloalkyl, preferably C₃-C₂₀-cycloalkyl,    alkenyl, preferably C₂-C₂₀-alkenyl, alkynyl, preferably    C₂-C₂₀-alkynyl, aryl, preferably C₆-C₂₄-aryl, carboxylate,    preferably C₁-C₂₀-carboxylate, alkoxy, preferably C₁-C₂₀-alkoxy,    alkenyloxy, preferably C₂-C₂₀-alkenyloxy, alkynyloxy, preferably    C₂-C₂₀-alkynyloxy, aryloxy, preferably C₆-C₂₄-aryloxy,    alkoxycarbonyl, preferably C₂-C₂₀-alkoxycarbonyl, alkylamino,    preferably C₁-C₃₀-alkylamino, alkylthio, preferably    C₁-C₃₀-alkylthio, arylthio, preferably C₆-C₂₄-arylthio,    alkylsulphonyl, preferably C₁-C₂₀-alkylsulphonyl, or alkylsulphinyl,    preferably C₁-C₂₀-alkylsulphinyl, where these groups may in each    case optionally be substituted by one or more alkyl, halogen,    alkoxy, aryl or heteroaryl moities or, as an alternative, the two    groups R together with the common carbon atom to which they are    bound are bridged to form a cyclic structure which can be aliphatic    or aromatic in nature, may be substituted and may contain one or    more heteroatoms.

Various representatives of the catalysts of the formula (A) are known inprinciple, e.g. from WO-A-96/04289 and WO-A-97/06185.

In preferred catalysts of the general formula (A), one group R ishydrogen and the other group R is C₁-C₂₀-alkyl, C₃-C₁₀-cycloalkyl,C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-carboxylate,C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy,C₂-C₂₀-alkoxycarbonyl, C₁-C₃₀-alkylamino, C₁-C₃₀-alkylthio,C₆-C₂₄-arylthio, C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl, wherethese moiety may in each case be substituted by one or more alkyl,halogen, alkoxy, aryl or heteroaryl groups.

Definition of X¹ and X²

In the catalysts of the general formula (A), X¹ and X² are identical ordifferent and are two ligands, preferably anionic ligands.

X¹ and X² can be, for example, hydrogen, halogen, pseudohalogen,straight-chain or branched C₁-C₃₀-alkyl, C₆-C₂₄-aryl, C₁-C₂₀-alkoxy,C₆-C₂₄-aryloxy, C₃-C₂₀-alkyldiketonate C₆-C₂₄-aryldiketonate,C₁-C₂₀-carboxylate, C₁-C₂₀-alkylsulphonate, C₆-C₂₄-arylsulphonate,C₁-C₂₀alkylthiol, C₆-C₂₄-arylthiol, C₁-C₂₀-alkylsulphonyl orC₁-C₂₀-alkylsulphinyl.

X¹ and X² can also be substituted by one or more further groups, forexample by halogen, preferably fluorine, C₁-C₁₀-alkyl, C₁-C₁₀-alkoxy orC₆-C₂₄-aryl, where these groups, too, may once again be substituted byone or more substituents selected from the group consisting of halogen,preferably fluorine, C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl.

In a preferred embodiment, X¹ and X² are identical or different and areeach halogen, in particular fluorine, chlorine, bromine or iodine,benzoate, C₁-C₅-carboxylate, C₁-C₅-alkyl, phenoxy, C₁-C₅-alkoxy,C₁-C₅-alkylthiol, C₆-C₂₄-arylthiol, C₆-C₂₄-aryl orC₁-C₅-alkylsulphonate.

In a particularly preferred embodiment, X¹ and X² are identical and areeach halogen, in particular chlorine, CF₃COO, CH₃COO, CFH₂COO, (CH₃)₃CO,(CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO, PhO (phenoxy), MeO (methoxy), EtO(ethoxy), tosylate (p-CH₃—C₆H₄—SO₃), mesylate (CH₃—SO₃) or CF₃SO₃(trifluoromethanesulphonate).

Definition of L

In the general formula (A), the symbols L represent identical ordifferent ligands and are preferably uncharged electron donating ligand.

The two ligands L can, for example, be, independently of one another, aphosphine, sulphonated phosphine, phosphate, phosphinite, phosphonite,arsine, stibine, ether, amine, amide, sulfonate, sulfoxide, carboxyl,nitrosyl, pyridine, thioether, imidazoline or imidazolidine (the lattertwo also being jointly referred to as “Im” ligand(s))

The term “phosphinite” includes, for example, phenyldiphenylphosphinite, cyclohexyl dicyclohexylphosphinite, isopropyldiisopropylphosphinite and methyl diphenylphosphinite

The term “phosphite” includes, for example, triphenyl phosphite,tricyclohexyl phosphite, tri-tert-butyl phosphite, triisopropylphosphite and methyl diphenyl phosphite.

The term “stibine” includes, for example, triphenylstibine,tricyclohexylstibine and trimethylstibine.

The term “sulfonate” includes, for example, trifluoromethanesulphonate,tosylate and mesylate.

The term “sulfoxide” includes, for example, (CH₃)₂S(═O) and (C₆H₅)₂S═O.

The term “thioether” includes, for example, CH₃SCH₃, C₆H₅SCH₃,CH₃OCH₂CH₂SCH₃ and tetrahydrothiophene.

For the purposes of the present application, the term “pyridine” is usedas a collective term for all nitrogen-containing ligands as arementioned by, for example, Grubbs in WO-A-03/011455. Examples are:pyridine, picolines (including α-, β- and γ-picoline), lutidines(including 2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-lutidine), collidine(2,4,6-trimethylpyridine), trifluoromethylpyridine, phenylpyridine,4-(dimethylamino)pyridine, chloropyridines, bromopyridines,nitropyridines, quinoline, pyrimidine, pyrrole, imidazole andphenylimidazole.

In a preferred embodiment catalysts of general formula (A) are used inwhich one or both of ligands L represent an imidazoline or imidazolidineligand (also jointly referred to as “Im”—ligand in this applicationunless indicated otherwise), having a structure of general formulae(IIa) or (IIb), wherein the meaning of L can be identical or differentin case both ligands L have a structure according to (IIa) or (IIb),

where

-   R⁸, R⁹, R¹⁰ and R¹¹ are identical or different and represent    hydrogen, straight-chain or branched C₁-C₃₀-alkyl,    C₃-C₂₀-cycloalkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,    C₇-C₂₅-alkaryl, C₂-C₂₀ heteroaryl, C₂-C₂₀ heterocyclyl,    C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₀-aryloxy,    C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀ alkylthio, C₆-C₂₀-arylthio, —Si(R)₃,    —O—Si(R)₃, —O—C(═O)R, C(═O)R, —C(═O)N(R)₂, —NR—C(═O)—N(R)₂,    —SO₂N(R)₂, —S(═O)R, —S(═O)₂R, —O—S(═O)₂R, halogen, nitro or cyano,    wherein in all above occurrences relating to the meanings of R⁸, R⁹,    R¹⁰ and R¹¹ the group R is identical or different and represents    hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, aryl or heteroaryl.

If appropriate, one or more of R⁸, R⁹, R¹⁰, and R¹¹ can independently ofone another, be substituted by one or more substituents, preferablystraight-chain or branched C₁-C₁₀-alkyl, C₃-C₈-cycloalkyl, C₁-C₁₀-alkoxyor C₆-C₂₄-aryl, C₂-C₂₀ heteroaryl, C₂-C₂₀ heterocyclic, and a functionalgroup selected from the group consisting of hydroxy, thiol, thioether,ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylicacid, disulphide, carbonate, isocyanate, carbodiimide, carboalkoxy,carbamate and halogen, where these abovementioned substituents, to theextent chemically possible, may in turn be substituted by one or moresubstituents, preferably selected from the group consisting of halogen,in particular chlorine or bromine, C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl.

Merely in the interest of clarity, it may be added that the structuresof the imidazoline and imidazolidine ligand depicted in the generalformulae (IIa) and (IIb) in the present patent application areequivalent to the structures (IIa′) and (IIb′) which are frequently alsofound in the literature for this imidazoline and imidazolidine ligand,respectively, and emphasize the carbene character of the imidazoline andimidazolidine. This applies analogously to the associated preferredstructures (IIIa)-(IIIu) depicted below.

In a preferred embodiment of the catalysts of the general formula (A),

-   R⁸ and R⁹ are each identical or different and represent hydrogen,    C₆-C₂₄-aryl, straight-chain or branched C₁-C₁₀-alkyl, or form a    cycloalkyl or aryl structure together with the carbon atoms to which    they are bound.

More preferably

-   R⁸ and R⁹ are identical and are selected from the group consisting    of hydrogen, methyl, propyl, butyl and phenyl.

The preferred and more preferred meanings of R⁸ and R⁹ may besubstituted by one or more further substituents selected from the groupconsisting of straight-chain or branched C₁-C₁₀-alkyl or C₁-C₁₀-alkoxy,C₃-C₈-cycloalkyl, C₆-C₂₄-aryl, and a functional group selected from thegroup consisting of hydroxy, thiol, thioether, ketone, aldehyde, ester,ether, amine, imine, amide, nitro, carboxylic acid, disulphide,carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate and halogen,wherein all these substituents may in turn be substituted by one or moresubstituents, preferably selected from the group consisting of halogen,in particular chlorine or bromine, C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl.

-   R¹⁰ and R¹¹ are identical or different and preferably represent    straight-chain or branched C₁-C₁₀-alkyl, C₃-C₁₀-cycloalkyl,    C₆-C₂₄-aryl, particularly preferably phenyl, C₁-C₁₀-alkylsulfonate,    C₆-C₁₀-arylsulfonate.

More preferably

-   R¹⁰ and R¹¹ are identical and are selected from the group consisting    of i-propyl, neopentyl, adamantyl, phenyl, 2,6-diisopropylphenyl,    2,6-dimethylphenyl, or 2,4,6-trimethylphenyl.

These preferred meanings of R¹⁰ and R¹¹ may be substituted by one ormore further substituents selected from the group consisting ofstraight-chain or branched C₁-C₁₀-alkyl or C₁-C₁₀-alkoxy,C₃-C₈-cycloalkyl, C₆-C₂₄-aryl, and a functional group selected from thegroup consisting of hydroxy, thiol, thioether, ketone, aldehyde, ester,ether, amine, imine, amide, nitro, carboxylic acid, disulphide,carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate and halogen,wherein all these substituents may in turn be substituted by one or moresubstituents, preferably selected from the group consisting of halogen,in particular chlorine or bromine, C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl.

Particularly preferred are catalysts of general formula (A) in which oneor both of ligands L represent imidazoline and imidazolidine ligandshaving the structures (IIIa) to (IIIu), where “Ph” means in each casephenyl, “Bu” means butyl, “Mes” represents in each case2,4,6-trimethylphenyl, “Dipp” means in all cases 2,6-diisopropylphenyland “Dimp” means 2,6-dimethylphenyl, and wherein the meaning of L can beidentical or different in case both ligands L in general formula (A)have a structure according to (IIIa) to (IIIu),

In a further preferred embodiment of catalyst (A) one or both of theligands L may have the meaning of general formulae (IIc) or (IId),wherein the meaning of L can be identical or different in case bothligands L have a structure according to (IIc) or (IId),

wherein

-   R⁸, R⁹ and R¹⁰ may have all general, preferred, more preferred and    most preferred meanings as defined above in relation to general    formulae (IIa) and (IIb), and-   R¹⁵, R¹⁶ and R¹⁷ are identical or different and may represent alkyl,    cycloalkyl, alkoxy, aryl, aryloxy, or a heterocyclic group.

In general formulae (IIc) and (IId) R⁸, R⁹, R¹⁰, R¹⁵, R¹⁶ and R¹⁷ mayalso be substituted by one or more further, identical or differentsubstituents selected from the group consisting of straight-chain orbranched C₁-C₅-alkyl, in particular methyl, C₁-C₅-alkoxy, aryl and afunctional group selected from the group consisting of hydroxy, thiol,thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro,carboxylic acid, disulphide, carbonate, isocyanate, carbodiimide,carboalkoxy, carbamate and halogen.

In a more preferred embodiment the ligands L has the general formula(IId) wherein

-   R¹⁵, R¹⁶ and R¹⁷ are identical or different, even more preferably    identical, and can represent C₁-C₂₀ alkyl, C₃-C₈-cycloalkyl, C₁-C₂₀    alkoxy, C₆-C₂₀ aryl, C₆-C₂₀ aryloxy, C₂-C₂₀ heteroaryl or a C₂-C₂₀    heterocyclic group.

In an even more preferred embodiment the ligand L has the generalformula (IId) wherein

-   R¹⁵, R¹⁶ and R¹⁷ are identical and each selected from the group    consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl,    sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl,    3-methylbutyl, neopentyl, 1-ethylpropyl, n-hexyl, neophenyl,    cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl    cyclooctyl, phenyl, biphenyl, naphthyl, phenanthrenyl, anthracenyl,    tolyl, 2,6-dimethylphenyl, and trifluoromethyl.

In case one or both of the ligand L possess general formula (IId) itmost preferably represents PPh₃, P(p-Tol)₃, P(o-Tol)₃, PPh(CH₃)₂,P(CF₃)₃, P(p-FC₆H₄)₃, P(p-CF₃C₆H₄)₃, P(C₆H₄—SO₃Na)₃, P(CH₂C₆H₄—SO₃Na)₃,P(isopropyl)₃, P(CHCH₃(CH₂CH₃))₃, P(cyclopentyl)₃, P(cyclohexyl)₃,P(neopentyl)₃ or P(neophenyl)₃.

Particular preference is given to catalyst systems comprising one of thetwo catalysts below, which fall under the general formula (A) and havethe structures (IV) (Grubbs I catalyst) and (V) (Grubbs II catalyst),where Cy is cyclohexyl.

In a further embodiment, use can be made of a catalyst of the generalformula (A1),

where

-   X¹, X² and L can have the same general, preferred and particularly    preferred meanings as in the general formula (A),-   n is 0, 1 or 2,-   m is 0, 1, 2, 3 or 4 and-   R′ are identical or different and are alkyl, cycloalkyl, alkenyl,    alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy, aryloxy,    alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl or    alkylsulphinyl radicals which may in each case be substituted by one    or more alkyl, halogen, alkoxy, aryl or heteroaryl.

As preferred catalyst falling under the general formula (A1), it ispossible to use, for example, the catalyst of the formula (VI) below,where Mes is in each case 2,4,6-trimethylphenyl and Ph is phenyl.

This catalyst is referred to in literature as “Nolan catalyst” and knownfrom WO-A-2004/112951. The catalysts of general formula (A) as well asthe preferred and more preferred embodiments thereof can also be used inimmobilized form to prepare the novel catalyst compositions. Theimmobilization favourably occurs via a chemical bond of the complexcatalyst to the surface of a support material. Suited are e.g. complexcatalysts having the general formulae (support-1), (support-2), or(support-3), as depicted below, wherein M, Y, L, X¹, X², and R may haveall general, preferred, more preferred, particularly preferred and mostpreferred meanings listed above in this application for general formula(A) and wherein “supp” stands for the support material. Preferably thesupport material represents a macromolecular material, or silica gels.As macromolecular material synthetic polymers or resins may be used,with polyethylene glycol, polystyrenes or cross-linked polystyrenes(e.g. poly(styrene-divinylbenzene) copolymers (PS-DVB)) being even morepreferred. Such support material comprises functional groups on itssurface which are able to form covalent bonds to one of the ligands orsubstituents of the complex catalyst, like e.g. to the ligand L or X¹ orto the substituents R³ or R⁴ as shown in the below depicted formulae.

In such immobilized catalysts of general formulae formulae (support-1),(support-2), or (support-3) “supp” stands more preferably for apolymeric support, a resin, polyethyleneglycole, or silica gels havingone or more functional groups “X³” on their surface which are able toform a covalent bond to one of the ligands, like e.g. the L, R or X¹ asshown in the above formulae. Suitable functional groups “X³” on thesurface are hydroxyl, amino, thiol, carboxyl, C₁-C₂₀ alkoxy, C₁-C₂₀alkylthio, —Si(R)₃, —O—Si(R)₃, C₆-C₁₄ aryloxy, C₂-C₁₄ heterocyclic,sulfinyl, sulfonyl, —C(═O)R, —C(═O)OR, —C(═O)N(R)₂, —NR—C(═O)—N(R)₂,—SO₂N(R)₂, or —N(SO₂—R)₂ wherein in all above occurrences of R in X³ isidentical or different and shall mean H, C₁-C₆-alkyl, C₅-C₆-cycloalkyl,C₂-C₆-alkenyl, C₂-C₆-alkynyl, phenyl, imidazolyl, triazolyl, orpyridinyl moieties.

Polystyrene or cross-linked polystyrene is the preferred supportmaterial, even more preferably with hydroxyl groups on the surface toallow an easy coupling to the catalyst.

A further embodiment provides catalyst systems obtainable by using acatalyst of the general formula (B),

where

-   M is ruthenium or osmium,-   X¹ and X² are identical or different and are anionic ligands,-   R″ are identical or different and are organic moieties,-   Im is a substituted or unsubstituted imidazoline or imidazolidine    ligand and-   An is an anion.

The catalysts of the general formula (B) are known in principle (see,for example, Angew. Chem. Int. Ed. 2004, 43, 6161-6165).

X¹ and X² in the general formula (B) can have the same general,preferred and particularly preferred meanings as in the formula (A).

The imidazoline or imidazolidine ligand usually has a structure of thegeneral formulae (IIa) or (IIb) which have been mentioned above for thecatalyst of general formula (A) and can have all the structuresmentioned there as preferred, in particular those of the formulae(IIIa)-(IIIu).

In general formula (B) R″ are identical or different and are each astraight-chain or branched C₁-C₃₀-alkyl, C₅-C₃₀-cycloalkyl or aryl,where the C₁-C₃₀-alkyl moiety may be interrupted by one or more doubleor triple bonds or one or more heteroatoms, preferably oxygen ornitrogen.

Aryl is an aromatic radical having from 6 to 24 skeletal carbon atoms.As preferred monocyclic, bicyclic or tricyclic carbocyclic aromaticmoieties having from 6 to 10 skeletal carbon atoms, mention may be madeby way of example of phenyl, biphenyl, naphthyl, phenanthrenyl oranthracenyl.

Preference is given to R″ in the general formula (B) being identical andeach being phenyl, cyclohexyl, cyclopentyl, isopropyl, o-tolyl, o-xylylor mesityl.

A further alternative embodiment provides a catalyst system obtainableby using a catalyst of the general formula (C)

where

-   M is ruthenium or osmium,-   R¹³ and R¹⁴ are each, independently of one another, hydrogen,    C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,    C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy,    C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl,    C₁-C₂₀alkylthio, C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl,-   X³ is an anionic ligand,-   L² is an uncharged π-bonded ligand which may either be monocyclic or    polycyclic,-   L³ is a ligand selected from the group consisting of phosphines,    sulphonated phosphines, fluorinated phosphines, functionalized    phosphines having up to three aminoalkyl, ammonioalkyl, alkoxyalkyl,    alkoxycarbonylalkyl, hydrocarbonylalkyl, hydroxyalkyl or ketoalkyl    groups, phosphites, phosphinites, phosphonites, phosphinamines,    arsines stibines, ethers, amines, amides, imines, sulphoxides,    thioethers and pyridines,-   Y⁻ is a noncoordinating anion and-   n is 0, 1, 2, 3, 4 or 5.

A further alternative embodiment provides a catalyst system obtainableby using a catalyst of the general formula (D),

where

-   M is ruthenium or osmium,-   X¹ and X² are identical or different and are anionic ligands which    can have all meanings of X¹ and X² mentioned in the general    formulae (A) and (B),-   the symbols L represent identical or different ligands which can    have all general and preferred meanings of L mentioned in the    general formulae (A) and (B),-   R¹⁹ and R²⁰ are identical or different and are each hydrogen or    substituted or unsubstituted alkyl.

A further alternative embodiment provides a catalyst system according tothe invention obtainable by using a catalyst of the general formula (E),(F) or (G),

where

-   M is osmium or ruthenium,-   X¹ and X² are identical or different and are two ligands, preferably    anionic ligands,-   L is a ligand, preferably an uncharged electron donor,-   Z¹ and Z² are identical or different and are uncharged electron    donors,-   R²¹ and R²² are each, independently of one another, hydrogen alkyl,    cycloalkyl, alkenyl, alkynyl, aryl, carboxylate, alkoxy, alkenyloxy,    alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio,    alkylsulphonyl or alkylsulphinyl which are in each case substituted    by one or more substituents selected from among alkyl, halogen,    alkoxy, aryl or heteroaryl.

The catalysts of the general formulae (E), (F), and (G) are known inprinciple, e.g. from WO 2003/011455 A1, WO 2003/087167 A2,Organometallics 2001, 20, 5314 and Angew. Chem. Int. Ed. 2002, 41, 4038.The catalysts are commercially available or can be synthesized by thepreparative methods indicated in the abovementioned literaturereferences.

In the catalyst systems according to the invention, catalysts of thegeneral formulae (E), (F), and (G) can be used in which Z¹ and Z² areidentical or different and are uncharged electron donors. These ligandsare usually weakly coordinating. The ligands are typically optionallysubstituted heterocyclic groups. These can be five- or six-memberedmonocyclic groups having from 1 to 4, preferably from 1 to 3 andparticularly preferably 1 or 2, heteroatoms or bicyclic or polycyclicstructures made up of 2, 3, 4 or 5 five- or six-membered monocyclicgroups of this type, where all the abovementioned groups may in eachcase optionally be substituted by one or more alkyl, preferablyC₁-C₁₀-alkyl, cycloalkyl, preferably C₃-C₈-cycloalkyl, alkoxy,preferably C₁-C₁₀-alkoxy, halogen, preferably chlorine or bromine, aryl,preferably C₆-C₂₄-aryl, or heteroaryl, preferably C₅-C₂₃-heteroaryl,radicals which may in turn each be substituted by one or more moieties,preferably selected from the group consisting of halogen, in particularchlorine or bromine, C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl.

Examples of Z¹ and Z² encompass nitrogen-containing heterocycles such aspyridines, pyridazines, bipyridines, pyrimidines, pyrazines,pyrazolidines, pyrrolidines, piperazines, indazoles, quinolines,purines, acridines, bisimidazoles, picolylimines, imidazolines,imidazolidines and pyrroles.

Z¹ and Z² can also be bridged to one another to form a cyclic structure.In this case, Z¹ and Z² form a single bidentate ligand.

In the catalysts of the general formulae (E), (F), and (G) L can havethe same general, preferred and particularly preferred meanings as L inthe general formula (A) and (B).

In the catalysts of the general formulae (E), (F), and (G) R^(2′) andR²² are identical or different and are each alkyl, preferablyC₁-C₃₀-alkyl, particularly preferably C₁-C₂₀-alkyl, cycloalkyl,preferably C₃-C₂₀-cycloalkyl, particularly preferably C₃-C₈-cycloalkyl,alkenyl, preferably C₂-C₂₀-alkenyl, particularly preferablyC₂-C₁₆-alkenyl, alkynyl, preferably C₂-C₂₀-alkynyl, particularlypreferably C₂-C₁₆-alkynyl, aryl, preferably C₆-C₂₄-aryl, carboxylate,preferably C₁-C₂₀-carboxylate, alkoxy, preferably C₁-C₂₀-alkoxy,alkenyloxy, preferably C₂-C₂₀-alkenyloxy, alkynyloxy, preferablyC₂-C₂₀-alkynyloxy, aryloxy, preferably C₆-C₂₄-aryloxy, alkoxycarbonyl,preferably C₂-C₂₀-alkoxycarbonyl, alkylamino, preferablyC₁-C₃₀-alkylamino, alkylthio, preferably C₁-C₃₀-alkylthio, arylthio,preferably C₆-C₂₄-arylthio, alkylsulphonyl, preferablyC₁-C₂₀-alkylsulphonyl, or alkylsulphinyl, preferablyC₁-C₂₀-alkylsulphinyl, where the abovementioned substituents may besubstituted by one or more alkyl, halogen, alkoxy, aryl or heteroarylmoieties.

In the catalysts of the general formulae (E), (F), and (G) X¹ and X² areidentical or different and can have the same general, preferred andparticularly preferred meanings as indicated above for X¹ and X² in thegeneral formula (A).

Preference is given to using catalysts of the general formulae (E), (F),and (G) in which

-   M is ruthenium,-   X¹ and X² are both halogen, in particular chlorine,-   R¹ and R² are identical or different and are five- or six-membered    monocyclic groups having from 1 to 4, preferably from 1 to 3 and    particularly preferably 1 or 2, heteroatoms or bicyclic or    polycyclic structures made up of 2, 3, 4 or 5 five- or six-membered    monocyclic groups of this type, where all the abovementioned groups    may in each case be substituted by one or more moieties selected    from the group consisting of alkyl, preferably C₁-C₁₀-alkyl,    cycloalkyl, preferably C₃-C₈-cycloalkyl, alkoxy, preferably    C₁-C₁₀-alkoxy, halogen, preferably chlorine or bromine, aryl,    preferably C₆-C₂₄-aryl, or heteroaryl, preferably C₅-C₂₃-heteroaryl,-   Z¹ and Z² are identical or different and five- or six-membered    monocyclic groups having from 1 to 4, preferably from 1 to 3 and    particularly preferably 1 or 2, heteroatoms or bicyclic or    polycyclic structures made up of 2, 3, 4 or 5 five- or six-membered    monocyclic groups of this type, where all these abovementioned    groups may in each case optionally be substituted by one or more    alkyl, preferably C₁-C₁₀-alkyl, cycloalkyl, preferably    C₃-C₈-cycloalkyl, alkoxy, preferably C₁-C₁₀-alkoxy, halogen,    preferably chlorine or bromine, aryl, preferably C₆-C₂₄-aryl, or    heteroaryl, preferably C₅-C₂₃-heteroaryl, radicals which may in turn    each be substituted by one or more moieties, preferably selected    from the group consisting of halogen, in particular chlorine or    bromine, C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl,-   R²¹ and R²² are identical or different and are each C₁-C₃₀-alkyl    C₃-C₂₀-cycloalkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,    C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy,    C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl,    C₁-C₃₀-alkylamino, C₁-C₃₀-alkylthio, C₆-C₂₄-arylthio,    C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphinyl, and-   L has a structure of the above-described general formula (IIa) or    (IIb), in particular one of the formulae (IIIa) to (IIIu).

A particularly preferred catalyst coming under general formula (E) hasthe structure (XIX),

where R²³ and R²⁴ are identical or different and are each halogen,straight-chain or branched C₁-C₂₀-alkyl, C₁-C₂₀-heteroalkyl,C₁-C₁₀-haloalkyl, C₁-C₁₀-alkoxy, C₆-C₂₄-aryl, preferably bromine,phenyl, formyl, nitro, a nitrogen heterocycle, preferably pyridine,piperidine or pyrazine, carboxy, alkylcarbonyl, halocarbonyl, carbamoyl,thiocarbamoyl, carbamido, thioformyl, amino, dialkylamino, trialkylsilylor trialkoxysilyl.

The abovementioned meanings for R²³ and R²⁴ C₁-C₂₀-alkyl,C₁-C₂₀-heteroalkyl, C₁-C₁₀-haloalkyl, C₁-C₁₀-alkoxy, C₆-C₂₄-aryl,preferably phenyl, formyl, nitro, a nitrogen heterocycle, preferablypyridine, piperidine or pyrazine, carboxy, alkylcarbonyl, halocarbonyl,carbamoyl, thiocarbamoyl, carbamido, thioformyl, amino, trialkylsilyland trialkoxysilyl may in turn each be substituted by one or morehalogen, preferably fluorine, chlorine or bromine, C₁-C₅-alkyl,C₁-C₅-alkoxy or phenyl moities.

Particularly preferred embodiments of the catalyst of formula (XIX) havethe structure (XIX a) or (XIX b), where R²³ and R²⁴ have the samemeanings as indicated in formula (XIX).

When R²³ and R²⁴ are each bromine in formula (XIXa), the catalyst isreferred to in the literature as the “Grubbs III catalyst”.

Further suitable catalysts which come under general formulae (E), (F),and (G) have the structural formulae (XX)-(XXXII), where Mes is in eachcase 2,4,6-trimethylphenyl.

A further embodiment relates to a catalyst system according to theinvention obtainable by using a catalyst (N) which has the generalstructural element (N1), where the carbon atom denoted by “*” is boundvia one or more double bonds to the catalyst framework with a rutheniumor osmium central metal,

and where

-   R²⁵-R³² are identical or different and are each hydrogen, halogen,    hydroxyl, aldehyde, keto, thiol, CF₃, nitro, nitroso, cyano,    thiocyano, isocyanato, carbodiimide, carbamate, thiocarbamate,    dithiocarbamate, amino, amido, imino, silyl, sulphonate (—SO₃),    —OSO₃ ⁻, —PO₃ ⁻ or OPO₃ ⁻ or alkyl, cycloalkyl, alkenyl, alkynyl,    aryl, carboxylate, alkoxy, alkenyloxy, alkynyloxy, aryloxy,    alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl,    alkylsulphinyl, dialkylamino, alkylsilyl or alkoxysilyl, where all    these moieties can each optionally be substituted by one or more    alkyl, halogen, alkoxy, aryl or heteroaryl substituents, or, as an    alternative, two directly adjacent substituents from the group    consisting of R²⁵-R³² together with the ring carbons to which they    are bound form a cyclic group, preferably an aromatic system, by    bridging or, as an alternative, R⁸ is optionally bridged to another    ligand of the ruthenium- or osmium-carbene complex catalyst,-   m is 0 or 1 and-   A is oxygen, sulphur, C(R³³R³⁴), N—R³⁵, —C(R³⁶)═C(R³⁷)—,    —C(R³⁶)(R³⁸)—C(R³⁷)(R³⁹)—, where R³³-R³⁹ are identical or different    and can each have the same meanings as R²⁵-R³².

In the catalysts having the structural element of the general formula(N1) the carbon atom denoted by “*” is bound via one or more doublebonds to the catalyst framework. If the carbon atom denoted by “*” isbound via two or more double bonds to the catalyst framework, thesedouble bonds can be cumulated or conjugated.

Such catalysts (N) have been described in US-A-2009/0076226, which alsodiscloses their preparation.

The catalysts (N) having a structural element of the general formula(N1) include, for example, catalysts of the general formulae (N2a) and(N2b) below,

where

-   M is ruthenium or osmium,-   X¹ and X² are identical or different and are two ligands, preferably    anionic ligands,-   L¹ and L² are identical or different ligands, preferably uncharged    electron donors, where L² can alternatively also be bridged to the    radical R⁸,-   n is 0, 1, 2 or 3, preferably 0, 1 or 2,-   n′ is 1 or 2, preferably 1, and-   R²⁵-R³², m and A have the same meanings as in the general formula    (N1).

In the catalysts of the general formula (N2a), the structural element ofthe general formula (N1) is bound via a double bond (n=0) or via 2, 3 or4 cumulated double bonds (in the case of n=1, 2 or 3) to the centralmetal of the complex catalyst. In the catalysts of the general formula(N2b) suitable to be used for the catalyst systems according to theinvention, the structural element of the general formula (N1) is boundvia conjugated double bonds to the metal of the complex catalyst. Inboth cases, the carbon atom denoted by “*” as a double bond in thedirection of the central metal of the complex catalyst.

The catalysts of the general formulae (N2a) and (N2b) thus encompasscatalysts in which the general structural elements (N3)-(N9)

are bound via the carbon atom denoted by “*” via one or more doublebonds to the catalyst framework of the general formula (N10a) or (N10b)

where X¹ and X², L¹ and L², n, n′ and R²⁵-R³⁹ have the meanings givenfor the general formulae (N2a) and (N2b).

The Ru- or Os-based carbene catalysts resulting thereof typically havefive-fold coordination.

In the structural element of the general formula (N1),

-   R²⁵-R³² are identical or different and are each hydrogen, halogen,    hydroxyl, aldehyde, keto, thiol, CF₃, nitro, nitroso, cyano,    thiocyano, isocyanato, carbodiimide, carbamate, thiocarbamate,    dithiocarbamate, amino, amido, imino, silyl, sulphonate (—SO₃ ⁻),    —OSO₃ ⁻, —PO₃ ⁻ or OPO₃ ⁻ or alkyl, preferably C₁-C₂₀-alkyl, in    particular C₁-C₆-alkyl, cycloalkyl, preferably C₃-C₂₀-cycloalkyl, in    particular C₃-C₈-cycloalkyl, alkenyl, preferably C₂-C₂₀-alkenyl,    alkynyl, preferably C₂-C₂₀-alkynyl, aryl, preferably C₆-C₂₄-aryl, in    particular phenyl, carboxylate, preferably C₁-C₂₀-carboxylate,    alkoxy, preferably C₁-C₂₀-alkoxy, alkenyloxy, preferably    C₂-C₂₀-alkenyloxy, alkynyloxy, preferably C₂-C₂₀-alkynyloxy,    aryloxy, preferably C₆-C₂₄-aryloxy, alkoxycarbonyl, preferably    C₂-C₂₀-alkoxycarbonyl, alkylamino, preferably C₁-C₃₀-alkylamino,    alkylthio, preferably C₁-C₃₀-alkylthio, arylthio, preferably    C₆-C₂₄-arylthio, alkylsulphonyl, preferably C₁-C₂₀-alkylsulphonyl,    alkylsulphinyl, preferably C₁-C₂₀-alkylsulphinyl, dialkylamino,    preferably di(C₁-C₂₀-alkyl)amino, alkylsilyl, preferably    C₁-C₂₀-alkylsilyl, or alkoxysilyl, preferably C₁-C₂₀-alkoxysilyl,    where these moities can each be optionally substituted by one or    more alkyl, halogen, alkoxy, aryl or heteroaryl substituents, or, as    an alternative, in each case two directly adjacent substituents from    the group consisting of R²⁵-R³² together with the ring carbons to    which they are bound may also form a cyclic group, preferably an    aromatic system, by bridging or, as an alternative, R⁸ is optionally    bridged to another ligand of the ruthenium- or osmium-carbene    complex catalyst,-   m is 0 or 1 and-   A is oxygen, sulphur, C(R³³)(R³⁴), N—R³⁵, —C(R³⁶)═C(R³⁷)— or    —C(R³⁶)(R³⁸)—C(R³⁷)(R³⁹)—, where R³³-R³⁹ are identical or different    and can each have the same preferred meanings as the radicals R¹-R⁸.

C₁-C₆-Alkyl in the structural element of the general formula (N1) is,for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl,tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl,neopentyl, 1-ethylpropyl or n-hexyl.

C₃-C₈-Cycloalkyl in the structural element of the general formula (N1)is, for example, cyclopropyl, cyclobutyl, cylopentyl, cyclohexyl,cycloheptyl or cyclooctyl.

C₆-C₂₄-Aryl in the structural element of the general formula (N1)comprises an aromatic radical having from 6 to 24 skeletal carbon atoms.As preferred monocyclic, bicyclic or tricyclic carbocyclic aromaticradicals having from 6 to 10 skeletal carbon atoms, mention may be madeby way of example of phenyl, biphenyl, naphthyl, phenanthrenyl oranthracenyl.

X¹ and X² in the structural element of the general formula (N1) have thesame general, preferred and particularly preferred meanings indicatedfor catalysts of the general formula A.

In the general formulae (N2a) and (N2b) and analogously in the generalformulae (N10a) and (N10b), L¹ and L² are identical or differentligands, preferably uncharged electron donors, and can have the samegeneral, preferred and particularly preferred meanings indicated forcatalysts of the general formula (A).

Preference is given to catalysts of the general formulae (N2a) or (N2b)having a general structural unit (N1) in which

-   M is ruthenium,-   X¹ and X² are both halogen,-   n is 0, 1 or 2 in the general formula (N2a) or-   n′ is 1 in the general formula (N2b)-   L¹ and L² are identical or different and have the general or    preferred meanings indicated for the general formulae (N2a) and    (N2b),-   R²⁵-R³² are identical or different and have the general or preferred    meanings indicated for the general formulae (N2a) and (N2b),-   m is either 0 or 1,-   and, when m=1,-   A is oxygen, sulphur, C(C₁-C₁₀-alkyl)₂,    —C(C₁-C₁₀-alkyl)₂-C(C₁-C₁₀-alkyl)₂-,    —C(C₁-C₁₀-alkyl)=C(C₁-C₁₀-alkyl)- or —N(C₁-C₁₀-alkyl).

Very particular preference is given to catalysts of the general formulae(N2a) or (N2b) having a general structural unit (N1) in which

-   M is ruthenium,-   X¹ and X² are both chlorine,-   n is 0, 1 or 2 in the general formula (N2a) or-   n′ is 1 in the general formula (N2b)-   L¹ is an imidazoline or imidazolidine ligand of one of the formulae    (IIIa) to (IIIu),-   L² is a sulphonated phosphine, phosphate, phosphinite, phosphonite,    arsine, stibine, ether, amine, amide, sulphoxide, carboxyl,    nitrosyl, pyridine radical, an imidazolidine radical of one of the    formulae (XIIa) to (XIIf) or a phosphine ligand, in particular PPh₃,    P(p-Tol)₃, P(o-Tol)₃, PPh(CH₃)₂, P(CF₃)₃, P(p-FC₆H₄)₃,    P(p-CF₃C₆H₄)₃, P(C₆H₄—SO₃Na)₃, P(CH₂C₆H₄—SO₃Na)₃, P(isopropyl)₃,    P(CHCH₃(CH₂CH₃))₃, P(cyclopentyl)₃, P(cyclohexyl)₃, P(neopentyl)₃    and P(neophenyl)₃,-   R²⁵-R³² have the general or preferred meanings indicated for the    general formulae (N2a) and (N2b),-   m is either 0 or 1-   and, when m=1,-   A is oxygen, sulphur, C(C₁-C₁₀-alkyl)₂,    —C(C₁-C₁₀-alkyl)₂-C(C₁-C₁₀-alkyl)₂-,    —C(C₁-C₁₀-alkyl)=C(C₁-C₁₀-alkyl)- or —N(C₁-C₁₀-alkyl).

When R²⁵ is bridged to another ligand of the catalyst of the formula N,this results, for example for the catalysts of the general formulae(N2a) and (N2b), in the following structures of the general formulae(N13a) and (N13b)

where

-   Y¹ is oxygen, sulphur, N—R⁴¹ or P—R⁴¹, where R⁴¹ has the meanings    indicated below,-   R⁴⁰ and R⁴¹ are identical or different and are each alkyl,    cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy,    aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio,    alkylsulphonyl or alkylsulphinyl which may each be optionally    substituted by one or more alkyl, halogen, alkoxy, aryl or    heteroaryl substituents,-   p is 0 or 1 and-   Y² when p=1 is —(CH₂)_(r)— where r=1, 2 or 3, —C(═O)—CH₂—, —C(═O)—,    —N═CH—, —N(H)—C(═O)— or, as an alternative, the entire structural    unit “—Y¹ (R⁴⁰)—(Y²)_(p)” is (—N(R⁴⁰)═CH—CH₂—),    (—N(R⁴⁰,R⁴¹)═CH—CH₂—), and    where M, X¹, X², L¹, R²⁵-R³², A, m and n have the same meanings as    in general formulae (N2a) and (N2b).

As examples of catalysts of the formula (N), mention is made of thefollowing structures:

Step a) of the Process According to the Present Invention:

The preparation of the novel catalyst composition in step a) of thepresent process is performed at an appropriate temperature. The choiceof the temperature is influenced by the nature of the co-catalyst andthe boiling temperature thereof. Typically this preparation step a) isperformed at a temperature in the range of from −20° C. to 160° C.,preferably in the range of from 20° C. to 80° C. The suitable time forthe catalyst pretreatment using vinyl-containing substance ranges fromabout 1 minute to 48 hours.

The ratio of the transition metal catalyst to the co-catalyst is1:(20-550), preferably 1:(20-500), more preferably 1:(25-475), even morepreferably 1:(25-450) and most preferably 1:(30-450).

In a preferred embodiment the molar ratio of the complex catalyst to theco-catalyst in a range of from 1:(20 to below 100), preferably 1:(25 to99.5), more preferably 1:(30 to 99), even more preferably 1:(35 to 98.5)and most preferably 1:(40 tp 70).

The preparation of the novel catalyst composition can be carried out inthe presence or absence of a suitable solvent which does not deactivatethe catalyst used and also does not have an adverse effect on thehydrogenation in any other way. Preferably an organic solvent is used todissolve the complex catalyst. More preferred solvents include, but arenot restricted to, dichloromethane, benzene, toluene, methyl ethylketone, acetone, tetrahydrofuran, tetrahydropyran, dioxane, cyclohexaneand chlorobenzene. The particularly preferred solvents are chlorobenzeneand methyl ethyl ketone. Typically the vinyl compound is added to thesolution of the complex catalyst.

The formation of the novel catalyst composition is performed beforehydrogen is brought into the reaction system.

Step b) of the Process According to the Present Invention:

Thereafter the hydrogenation of the nitrile rubber is carried out bybringing the nitrile rubber into contact with hydrogen and the catalystcomposition formed in step a) of the present process.

The hydrogenation is preferably carried out at a temperature in therange of from 60° C. to 200° C., preferably from 80° C. to 180° C., mostpreferably from 100° C. to 160° C. and at a hydrogen pressure in therange of 0.5 MPa to 35 MPa, more preferably of 3.0 MPa to 10 MPa.

Preferably, the hydrogenation time of the nitrile rubber is from 10minutes to 24 hours, preferably from 15 minutes to 20 hours, morepreferably from 30 minutes to 12 hours, even more preferably from 1 hourto 8 hours and most preferably from 1 hour to 4 hours.

The amount of the catalyst composition which is present in thehydrogenation step b) based on the nitrile rubber can be chosen in abroad range, preferably so that from 1 to 1000 ppm of ruthenium orosmium, preferably from 2 to 500 ppm, in particular from 5 to 250 ppm,are present based on the nitrile rubber used.

In an alternative embodiment of the present process it is possible toperform a metathesis reaction prior to the preparation of the novelcatalyst composition and the subsequent hydrogenation. Such alternativeprocess (hereinafter also referred to as “tandem process”) comprisesperforming a metathesis step before the above described steps a) and b).

This means that such alternative process comprises firstly subjecting anitrile rubber to a molecular weight degradation in a metathesisreaction comprising contacting the nitrile rubber in the absence orpresence of a co-olefin with a complex catalyst based on ruthenium orosmium as central metal and bearing at least one ligand which is boundto the ruthenium or osmium central metal in a carbene-like fashion, then

-   a) contacting the complex catalyst which is present in the reaction    mixture obtained after the metathesis reaction with at least one    co-catalyst having at least one vinyl group in a molar ratio of the    complex catalyst to the co-catalyst in the range of 1:(20-550) to    form a catalyst composition and thereafter-   b) hydrogenating the nitrile rubber in the presence of the catalyst    composition.

In a preferred embodiment of this alternative process the molar ratio ofthe complex catalyst to the co-catalyst in a range of from 1:(20 tobelow 100), preferably 1:(25 to 99.5), more preferably 1:(30 to 99),even more preferably 1:(35 to 98.5) and most preferably 1:(40 to 70).

Metathesis Step a) of the Tandem Method:

The NBR metathesis as first step of the tandem method can be carried outin the absence or presence of a co-olefin.

This co-olefin is preferably a straight-chain or branched C₂-C₁₆-olefin.Suitable co-olefins are, for example, ethylene, propylene, isobutene,styrene, 1-hexene and 1-octene. Particular preference is given to using1-hexene or 1-octene.

In the alternative the following functionalized co-olefins can be used:

If the co-olefin is liquid (as in the case of, for example, 1-hexene),the amount of co-olefin is preferably in the range 0.2-20% by weight,based on the nitrile rubber used. If the co-olefin is a gas, as in thecase of, for example, ethylene, the amount of co-olefin is selected sothat a pressure in the range 1×10⁵ Pa-1×10⁷ Pa, preferably a pressure inthe range from 5.2×10⁵ Pa to 4×10⁶ Pa, is established in the reactionvessel at room temperature.

The metathesis reaction can be carried out in a suitable solvent whichdoes not deactivate the catalyst used and also does not have an adverseeffect on the reaction in any other way. Preferred solvents include, butare not restricted to, dichloromethane, benzene, toluene, methyl ethylketone, acetone, tetrahydrofuran, tetrahydropyran, dioxane, cyclohexaneand chlorobenzene. The particularly preferred solvent is chlorobenzene.In some cases when the co-olefin itself can function as solvent, e.g. inthe case of 1-hexene, the addition of a further additional solvent canbe dispensed with.

The amount of catalyst based on the nitrile rubber used in themetathesis step of the tandem method according to the invention dependson the nature and the catalytic activity of the specific complexcatalyst. The amount of catalyst used is usually from 1 to 1000 ppm ofnoble metal, preferably from 2 to 500 ppm, in particular from 5 to 250ppm, based on the nitrile rubber used.

The concentration of the nitrile rubber used in the reaction mixture ofthe metathesis is not critical, but it should naturally be ensured thatthe reaction is not adversely affected by an excessively high viscosityof the reaction mixture and the associated mixing problems. Theconcentration of NBR in the reaction mixture is preferably in the rangefrom 1 to 25% by weight, particularly preferably in the range from 5 to20% by weight, based on the total reaction mixture.

The metathetic degradation is usually carried out at a temperature inthe range from 10° C. to 150° C., preferably at a temperature in therange from 20 to 80° C.

The metathesis reaction time depends on a number of factors, for exampleon the type of NBR, the type of catalyst, the catalyst concentration andco-olefin concentration used and the reaction temperature. The progressof the cross-metathesis can be monitored by standard analytical methods,e.g. by GPC measurements or by determination of the viscosity. Thereaction is typically allowed to be conducted for about 15 minutes tosix hours under normal conditions. It is also possible to perform themetathesis reaction until the reaction ceases by deactivation of thecatalyst.

After such metathesis step, the reaction mixture containing themetathesis catalyst is taken and brought into contact with theco-catalyst having the general formula (1) or (2). Typically theco-catalyst is simply added to the reaction mixture, preferably in thesame solvent in which the metathesis was performed.

The appropriate temperature for the preparation of the novel catalystcomposition after the metathesis in the tandem method can also be chosenin the range of from −20° C. to 160° C., preferably in the range of from20° C. to 80° C. The suitable time for the preparation of the catalystcomposition for the subsequent hydrogenation reaction in such tandemreaction using the vinyl-group containing co-catalyst ranges from about5 minutes to 48 hours. The preferred time ranges from 10 minutes to 12hours.

The subsequent hydrogenation of the nitrile rubber can be carried in thesame manner as described above for the hydrogenation reaction.

One major advantage of the present invention resides in the fact thatthe catalyst composition used is very active, so that the catalystresidue in the final HNBR products can be low enough to make thecatalyst metal removal or recycle step alleviated or even unnecessary.However, to the extent desired, the catalysts used during the process ofthe present invention may be removed. Such removal can be performed e.g.by using ion-exchange resins as described in EP-A-2 072 532 A1 andEP-A-2 072 533 A1. The reaction mixture obtained after the completion ofthe hydrogenation reaction can be taken and treated with an ion-exchangeresin at e.g. 100° C. for 48 hours under nitrogen and then beprecipitated in cold methanol

Nitrile Rubber:

The nitrile rubber used in the process of the present invention is acopolymer or terpolymer of at least one α,β-unsaturated nitrile, atleast one conjugated diene and, if desired, one or more furthercopolymerizable monomers.

The conjugated diene can be of any nature. Preference is given to using(C₄-C₆) conjugated dienes. Particular preference is given to1,3-butadiene, isoprene, 2,3-dimethylbutadiene, piperylene or mixturesthereof. Very particular preference is given to 1,3-butadiene andisoprene or mixtures thereof. Especial preference is given to1,3-butadiene.

As α,β-unsaturated nitrile, it is possible to use any knownα,β-unsaturated nitrile, preferably a (C₃-C₅) α,β-unsaturated nitrilesuch as acrylonitrile, methacrylonitrile, ethacrylonitrile or mixturesthereof. Particular preference is given to acrylonitrile.

A particularly preferred nitrile rubber used in the process of thisinvention is thus a copolymer having repeating units derived fromacrylonitrile and 1,3-butadiene.

Apart from the conjugated diene and the α,β-unsaturated nitrile, thehydrogenated nitrile rubber may comprise repeating units of one or morefurther copolymerizable monomers known in the art, e.g. α,β-unsaturated(preferably mono-unsaturated) monocarboxylic acids, their esters andamides, α,β-unsaturated (preferably mono-unsaturated) dicarboxylicacids, their mono-oder diesters, as well as the respective anhydrides oramides of said α,β-unsaturated dicarboxylic acids.

As α,β-unsaturated monocarboxylic acids acrylic acid and methacrylicacid are preferably used.

Esters of α,β-unsaturated monocarboxylic acids may also be used, inparticular alkyl esters, alkoxyalkyl esters, aryl esters,cycloalkylesters, cyanoalkyl esters, hydroxyalkyl esters, andfluoroalkyl esters.

As alkyl esters C₁-C₁₈ alkyl esters of the α,β-unsaturatedmonocarboxylic acids are preferably used, more preferably C₁-C₁₈ alkylesters of acrylic acid or methacrylic acid, such as methylacrylate,ethylacrylate, propylacrylate, n-butylacrylate, tert.-butylacrylate,2-ethyl-hexylacrylate, n-dodecylacrylate, methylmethacrylate,ethylmethacrylate, propylmethacrylate, n-butylmethacrylate,tert.-butylmethacrylate and 2-ethylhexyl-methacrylate.

As alkoxyalkyl esters C₂-C₁₈ alkoxyalkyl esters of α,β-unsaturatedmonocarboxylic acids are preferably used, more preferablyalkoxyalkylester of acrylic acid or methacrylic acid such as methoxymethyl(meth)acrylate, methoxy ethyl(meth)acrylate,ethoxyethyl(meth)acrylate and methoxyethyl(meth)acrylate.

It is also possible to use aryl esters, preferably C₆-C₁₄-aryl-, morepreferably C₆-C₁₀-aryl esters and most preferably the aforementionedaryl esters of acrylates and methacrylates.

In another embodiment cycloalkyl esters, preferably C₅-C₁₂—, morepreferably C₆-C₁₂-cyclo-alkyl and most preferably the aforementionedcycloalkyl acrylates and methacrylates are used.

It is also possible to use cyanoalkyl esters, in particular cyanoalkylacrylates or cyanoalkyl methacrylates, with 2 to 12 C atoms in thecyanoalkyl group, preferably α-cyanoethyl acrylate, β-cyanoethylacrylate or cyanobutyl methacrylate.

In another embodiment hydroxyalkyl esters are used, in particularhydroxyalkyl acrylates and hydroxyalkyl methacrylates with 1 to 12C-atoms in the hydroxylalkyl group, preferably 2-hydroxyethyl acrylate,2-hydroxyethyl methacrylate or 3-hydroxypropyl acrylate.

It is also possible to use fluorobenzyl esters, in particularfluorobenzyl acrylates or fluorobenzyl methacrylates, preferablytrifluoroethyl acrylate and tetrafluoropropyl methacrylate. Substitutedamino group containing acrylates and methacrylates may also be used likedimethylaminomethyl acrylate and diethylaminoethylacrylate.

Various other esters of the α,β-unsaturated carboxylic acids may also beused, like e.g. poly-ethyleneglycol(meth)acrylate,polypropyleneglycole(meth)acrylate, glycidyl(meth)acrylate,epoxy(meth)acrylate, N-(2-hydroxyethyl)acrylamide,N-(2-hydroxymethyl)acrylamide or urethane(meth)acrylate.

It is also possible to use mixture of all aforementioned esters ofα,β-unsaturated carboxylic acids.

Furthon α,β-unsaturated dicarboxylic acids may be used, preferablymaleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acidand mesaconic acid.

In another embodiment anhydrides of α,β-unsaturated dicarboxylic acidsare used, preferably maleic anhydride, itaconic anhydride, itaconicanhydride, citraconic anhydride and mesaconic anhydride.

In a further embodiment mono- or diesters of α,β-unsaturateddicarboxylic acids can be used. Suitable alkyl esters are e.g.C₁-C₁₀-alkyl, preferably ethyl-, n-propyl-, iso-propyl, n-butyl-,tert.-butyl, n-pentyl-oder n-hexyl mono- or diesters. Suitablealkoxyalkyl esters are e.g. C₂-C₁₂ alkoxyalkyl-, preferablyC₃-C₈-alkoxyalkyl mono- or diesters. Suitable hydroxyalkyl esters aree.g. C₁-C₁₂ hydroxyalkyl-, preferably C₂-C₈-hydroxyalkyl mono- ordiesters. Suitable cycloalkyl esters are e.g. C₅-C₁₂-cycloalkyl-,preferably C₆-C₁₂-cycloalkyl mono- or diesters. Suitable alkylcycloalkylesters are e.g. C₆-C₁₂-alkylcycloalkyl-, preferablyC₇-C₁₀-alkylcycloalkyl mono- or diesters. Suitable aryl esters are e.g.C₆-C₁₄-aryl, preferably C₆-C₁₀-aryl mono- or diesters.

Explicit examples of the α,β-ethylenically unsaturated dicarboxylic acidmonoester monomers include

-   -   maleic acid monoalkyl esters, preferably monomethyl maleate,        monoethyl maleate, monopropyl maleate, and mono n-butyl maleate;    -   maleic acid monocycloalkyl esters, preferably monocyclopentyl        maleate, monocyclohexyl maleate, and monocycloheptyl maleate;    -   maleic acid monoalkylcycloalkyl esters, preferably        monomethylcyclopentyl maleate, and monoethylcyclohexyl maleate;    -   maleic acid monoaryl ester, preferably monophenyl maleate;    -   maleic acid mono benzyl ester, preferably monobenzyl maleate;    -   fumaric acid monoalkyl esters, preferably monomethyl fumarate,        monoethyl fumarate, monopropyl fumarate, and mono n-butyl        fumarate;    -   fumaric acid monocycloalkyl esters, preferably monocyclopentyl        fumarate, monocyclohexyl fumarate, and monocycloheptyl fumarate;    -   fumaric acid monoalkylcycloalkyl esters, preferably        monomethylcyclopentyl fumarate, and monoethylcyclohexyl        fumarate;    -   fumaric acid monoaryl ester, preferably monophenyl fumarate;    -   fumaric acid mono benzyl ester, preferably monobenzyl fumarate;    -   citraconic acid monoalkyl esters, preferably monomethyl        citraconate, monoethyl citraconate, monopropyl citraconate, and        mono n-butyl citraconate;    -   citraconic acid monocycloalkyl esters, preferably        monocyclopentyl citraconate, monocyclohexyl citraconate, and        monocycloheptyl citraconate;    -   citraconic acid monoalkylcycloalkyl esters, preferably        monomethylcyclopentyl citraconate, and monoethylcyclohexyl        citraconate;    -   citraconic acid mono aryl ester, preferably monophenyl        citraconate;    -   citraconic acid mono benzyl ester, preferably monobenzyl        citraconate;    -   itaconic acid mono alkyl esters, preferably monomethyl        itaconate, monoethyl itaconate, monopropyl itaconate, and mono        n-butyl itaconate;    -   itaconic acid monocycloalkyl esters, preferably monocyclopentyl        itaconate, monocyclohexyl itaconate, and monocycloheptyl        itaconate;    -   itaconic acid monoalkylcycloalkyl esters, preferably        monomethylcyclopentyl itaconate, and monoethylcyclohexyl        itaconate;    -   itaconic acid mono aryl ester, preferably monophenyl itaconate;    -   itaconic acid mono benzyl ester, preferably monobenzyl        itaconate.

As α,β-ethylenically unsaturated dicarboxylic acid diester monomers theanaloguos diesters based on the above explicitely mentioned mono estermonomers may be used, wherein, however, the two organic groups linked tothe C═O group via the oxygen atom may be identical or different.

As further termonomers vinyl aromatic monomers like styrol,α-methylstyrol and vinylpyridine, as well as non-conjugated dienes like4-cyanocyclohexene and 4-vinylcyclohexene, as well as alkines like 1- or2-butine may be used.

Particularly preferred are termonomers chosen from the below depictedformulae:

where

-   R¹ is hydrogen or methyl group, and-   R², R³, R⁴, R⁵ are identical or different and may represent H,    C₁-C₁₂ alkyl, cycloalkyl, alkoxyalkyl, hydroxyalkyl, expoxyalkyl,    aryl, heteroaryl.

The proportions of conjugated diene and α,β-unsaturated nitrile in theNBR polymers to be used can vary within wide ranges. The proportion ofthe conjugated diene or the sum of conjugated dienes is usually in therange from 40 to 90% by weight, preferably in the range from 60 to 85%by weight, based on the total polymer. The proportion of α,β-unsaturatednitrile or the sum of α,β-unsaturated nitriles is usually from 10 to 60%by weight, preferably from 15 to 40% by weight, based on the totalpolymer. The proportions of the monomers in each case add up to 100% byweight. The additional monomers can be present in amounts of from 0 to40% by weight, preferably from 0.1 to 40% by weight, particularlypreferably from 1 to 30% by weight, based on the total polymer. In thiscase, corresponding proportions of the conjugated diene or dienes and/orthe α,β-unsaturated nitrile or nitriles are replaced by proportions ofthe additional monomers, with the proportions of all monomers in eachcase adding up to 100% by weight.

The preparation of the nitrite rubbers by polymerization of theabovementioned monomers is adequately known to those skilled in the artand is comprehensively described in the literature. Nitrile rubberswhich can be used for the purposes of the invention are alsocommercially available, e.g. as products from the product range of thePerbunan® and Krynac® grades of Lanxess Deutschland GmbH.

The nitrile rubbers to be hydrogenated have a Mooney viscosity (ML1+4 at100° C.), measured in accordance with ASTM standard D 1646, in the rangefrom 1 to 75, and preferably from 5 to 50. The weight average molecularweight Mw is in the range 2,000-500,000 g/mol, preferably in the range20,000-400,000. The nitrile rubbers have a polydispersity PDI=Mw/Mn,where Mw is the weight average molecular weight and Mn is the numberaverage molecular weight, in the range 1-5. The determination of theMooney viscosity is carried out in accordance with ASTM Standard D 1646.

As the metathesis activity of the ruthenium- or osmium-based catalystused to prepare the catalyst composition according to this invention isnot existing in the catalyst composition of the present invention themolecular weight of the hydrogenated nitrile rubber obtained after thehydrogenation is comparable to the original NBR feedstock and notfurther reduced during hydrogenation.

Hence, a hydrogenated nitrile rubber with a weight average molecularweight Mw in the range 2,000-500,000 g/mol, preferably in the range20,000-400,000 is obtained. The Mooney viscosity (ML1+4 at 100° C.),measured in accordance with ASTM standard D 1646, of the hydrogenatednitrile rubbers is in the range from 1 to 150, preferably from 10 to100. The polydispersity PDI=Mw/Mn, where Mw is the weight averagemolecular weight and Mn is the number average molecular weight, in therange 1-5 and preferably in the range 1.5-4.

For the purposes of the present invention, hydrogenation is a reactionof the double bonds present in the starting nitrile rubber to an extentof at least 50%, preferably 70-100%, more preferably 80-100%; even morepreferably 90-100%

In the tandem method, the nitrile rubber is firstly degraded using atleast one ruthenium- or osmium-based catalyst in the absence or in thepresence of a co-olefin. The vinyl compound of general formula (1) iseither added when the metathesis reaction has ceased or gone tocompletion or added before in order to stop the metathesis at a certaindegree. Thereafter, the hydrogenation can be carried out to affordhydrogenated nitrile rubber by introducing hydrogen gas. In the sequenceof metathesis, catalyst composition formation and hydrogenation, themetathesis degree can be fully controlled and the molecular weight ofthe final hydrogenated nitrile rubber is adjustable as desired. Thenitrile rubbers subjected to metathesis in the tandem method maytypically have a Mooney viscosity (ML1+4 at 100° C.), measured inaccordance with ASTM standard D 1646, in the range from 30 to 75, andpreferably from 30 to 50. The weight average molecular weight Mw is inthe range 150,000-500,000 g/mol, preferably in the range180,000-400,000. These nitrile rubbers have a polydispersity PDI=Mw/Mn,where Mw is the weight average molecular weight and Mn is the numberaverage molecular weight, in the range 2 tp 6. The determination of theMooney viscosity is carried out in accordance with ASTM Standard D 1646.

The invention is further illustrated but is not intended to be limitedby the following examples in which all parts and percentages are byweight unless otherwise specified.

EXAMPLES Catalysts Used in the Examples

Catalysts (1) to (3) were purchased from Sigma Aldrich or StremChemicals Inc. Catalyst (4) was purchased from Xian Kaili Co. (China).The structures of these catalysts are shown below, wherein “Mes” meansmesityl (2,4,6-trimethylphenyl) and “Cy” means cyclohexyl:

These catalysts have the following molecular weights:

molecular weight catalyst [g/mol] (1) 822.96 (2) 848.97 (3) 885.55 (4)925.22

Nitrile Butadiene Rubbers Used in the Examples:

The nitrile butadiene rubbers used in the examples had the propertiesoutlined in Table 1.

TABLE 1 Nitrile Butadiene Rubbers (NBR) used (“ACN” means acrylonitrile)Mooney viscosity ACN content ML(1 + 4) NBR % by weight 100° C. Mn Mw PDIPerbunan ® 34 29 77,101 255,395 3.31 3431 VP NBR-5 34 34 73,711 243,6713.31 NBR-6 34 34 74,698 249,935 3.35 NBR-7 34 34 70,674 251,292 3.56

Vinyl ethyl ether (VEE) was purchased from Sigma-Aldrich.

Analytical Tests: GPC Test:

The apparent molecular weight Mn and Mw were determined by a Waters GPCsystem equipped with a Waters 1515 high performance liquidchromatography pump, a Waters 717plus autosampler, a PL gel 10 μm mixedB column and a Waters 2414 RI detector. The GPC test was carried out at40° C. at 1 mL/min of flow rate with THF as the eluent, and the GPCcolumn was calibrated with narrow PS standard samples.

FT-IR Test:

The spectrum of nitrile rubber before, during and after thehydrogenation reaction was recorded on a Perkin Elmer spectrum 100 FT-IRspectrometer. The solution of the nitrile butadiene rubber in MCB wascast onto a KBr disk and dried to form a film for the test. Thehydrogenation conversion is determined by the FT-IR analysis accordingto the ASTM D 5670-95 method.

Abbreviations:

phr: per hundred rubber (weight)rpm: revolution per minuteMn: number-average molecular weightMw: weight-average molecular weightPDI: polydispersity index, defined as Mw/MnPPh₃: triphenylphosphineMCB: monochlorobenzeneVEE: vinyl ethyl etherRT: room temperature (22+/−2° C.)

Example 1 Comparison Example, Using Catalyst (4)

A solution of 18 g Perbunan® 3431VP in 282 g MCB (Perbunan® 3431VPconcentration of 6 wt %) was bubbled with nitrogen in a 600 mL Parrautoclave for 30 minutes, and then heated to 120° C. Wilkinson'scatalyst (15 mg) and PPh₃ (18 mg) was dissolved in another 22 g ofdegassed MCB and then added into the reactor. Hydrogenation wasconducted under 4.137 MPa of hydrogen pressure and 800 rpm of agitationspeed. Samples were taken from the reactor at intervals for FT-IRanalysis to determine the hydrogenation degree. After 5 hours ofhydrogenation, the hydrogenation degree reached 90.3%, the reactor wascooled to room temperature and the pressure was released. The finalmolecular weights and PDI were: Mn=76,286, Mw=260,572, PDI=3.42.

Examples 2 Inventive Example; Perbunan 3431VP; Catalyst (1); VEE asCo-Catalyst

Catalyst (1) (9 mg) was dissolved in 22 g degassed MCB in a flask. Vinylethyl ether (100 μL) was injected into the flask and the solution wasstirred for 12 hours. A solution of 18 g Perbunan® 3431VP in 282 g MCB(Perbunan®3431VP concentration of 6 wt %) was bubbled with nitrogen in a600 mL. Parr autoclave for 30 minutes, and then heated to 120° C. Thecatalyst solution in the flask was transferred into the reactor viasyringe. Hydrogenation was conducted under 4.137 Mpa of hydrogenpressure and 800 rpm of agitation speed. Samples were taken from thereactor at intervals for FT-IR analysis to determine the hydrogenationdegree. After 3 hours of hydrogenation, the hydrogenation degree reached93%. The final molecular weights and the PDI were:: Mn=75,844,Mw=223,863, PDI=2.95.

Example 3 Inventive Example; Perbunan 3431VP; Catalyst (2); VEE asCo-Catalyst

All the conditions and operation were the same as in Example 5 exceptthat Catalyst (2) was used (18 mg). The hydrogenation degree at 1 hourwas 99%. The final molecular weights and the PDI were: Mn=71,762,Mw=221,604, PDI=3.09.

Example 4 Inventive Example; Perbunan 3431VP; Catalyst (2); VEE asCo-Catalyst

All the conditions and operation were the same as in Example 5 exceptthat Catalyst (2) was used (9 mg). The hydrogenation degree at 2 hourswas 95%. The final molecular weights and the PDI were: Mn=71,274,Mw=208,575, PDI=2.93.

Example 5 Inventive Example; Perbunan 3431VP; Catalyst (3); VEE asCo-Catalyst

All the conditions and operation were the same as in Example 5 exceptthat Catalyst (3) was used (9 mg). The hydrogenation degree at 3 hourswas 98%. The final molecular weights and the PDI were: Mn=88,070,Mw=267,466, PDI=3.04.

The conditions and the results for Example 1-5 are shown in Table 2. Insuch Table 2 the comparative examples are marked with an asterisk.Furtheron the abbreviation P3431 VP stands for Perbunan® 3431VP. Onlyfor comparison reasons the number and weight average molecular weightsas well as PDI has been included at the bottom of Table 2 with regard tothe starting nitrile rubber then subjected to hydrogenation in Examples1 to 5.

TABLE 2 Examples 1 to 5 (for all examples: hydrogenation temperature:120° C. and pressure: 4.137 MPa) MCB NBR (used to Perbunan ® dissolve3431 VP* NBR + catalyst co-catalyst Molar ratio Time hydrogenationamount catalyst) amount amount co-catalyst of pretreatment time degreeMn Mw Ex [g] [g] no. [mg] [mmol] type [mg] [mmol] to catalyst [h] [h][%] [g/mol] [g/mol] PDI HNBR 1* 18 282 + 22 (4) 15 0.0162 PPh₃ 18 0 590.3 76,286 260,572 3.42 2 18 282 + 22 (1) 18 0.0219 VEE 75 1.04 47.5 123 93 75,844 223,863 2.95 3 18 282 + 22 (2) 18 0.0212 VEE 75 1.04 49.1 121 99 71,762 221,604 3.09 4 18 282 + 22 (2) 9 0.0106 VEE 75 1.04 98.1 122 95 71,274 208,575 2.93 5 18 282 + 22 (3) 9 0.0102 VEE 75 1.04 102.3 123 98 88,070 267,466 3.04 *Perbunan ® 3431 VP 77,101 255,395 3.31

Example 6 Comparison Example: NBR-5; Catalyst (2); First Metathesis, NoAdditional Treatment with a Co-Catalyst, then Hydrogenation

A solution of 270 g NBR-5 in 4,350 g MCB was bubbled with nitrogen in a10 L Pan autoclave for 30 minutes. 11.1 g 1-hexene dissolved in 50 gdegassed MCB were added into the reactor and the mixture was stirred for1 hour. Catalyst (2) (135 mg) was dissolved in another 100 g of degassedMCB, added into the reactor and metathesis was conducted for 1 hour.Then the reactor was heated to 140° C. and hydrogenation was conductedunder 8.4 MPa of hydrogen pressure and 600 rpm of agitation speed.Samples were taken from the reactor at intervals for FT-IR analysis todetermine the hydrogenation degree. After 2 hours of hydrogenation, thehydrogenation degree reached 99.5%. The final molecular weights and thePDI were: Mn=4,648, Mw=9,952, PDI=2.14.

Example 7 Inventive; NBR-6; Catalyst (2); Treatment with VEE asCo-Catalyst; Thereafter Hydrogenation

Catalyst (2) (135 mg) was dissolved in 100 g degassed MCB in a flask.Vinyl ethyl ether (0.75 g) was injected into the flask and the solutionwas stirred under nitrogen for 12 hours at room temperature. A solutionof 270 g NBR-6 in 4,350 g MCB was bubbled with nitrogen in 10 L Parrautoclave for 30 minutes, and then heated to 140° C. The catalystsolution in the flask was transferred into the reactor and 11.1 g1-hexene dissolved in 50 g degassed MCB were added into the reactor.Hydrogenation was conducted under 8.4 MPa of hydrogen pressure and 600rpm of agitation speed. Samples were taken from the reactor at intervalsfor FT-IR analysis to determine the hydrogenation degree. After 3 hoursof hydrogenation, the hydrogenation degree reached 99.4%. The finalmolecular weights and the PDI were: Mn=92,462, Mw=258,405, PDI=2.79.

Examples 8-10 Inventive, NBR-6, Catalyst (2); Metathesis, Treatment withVEE as Co-Catalyst and Subsequent Hydrogenation

A solution of 560 g NBR-6 in 4,516 g MCB (NBR-6 concentration of 11 wt %was bubbled with nitrogen in a 10 L Parr autoclave for 30 minutes. 23.1g 1-hexene dissolved in 50 mL degassed MCB were added into the reactorand the mixture was stirred for 1 hour. Catalyst (2) (280 mg) wasdissolved in 100 g of degassed MCB at room temperature and then addedinto the reactor. The metathesis was allowed to conduct for 15 min atroom temperature. Then 1.55 g of VEE dissolved in 200 g degassed MCB wasadded into the autoclave. After stirring for 1 hour, a sample was takenfrom the reactor for GPC analysis. The temperature of the autoclave waselevated to 140° C. Then the hydrogen gas was introduced into theautoclave. Hydrogenation was conducted under 8.4 MPa of hydrogenpressure and 600 rpm of agitation speed. Samples were taken from thereactor at intervals for FT-IR analysis to determine the hydrogenationdegree. The molecular weights and the PDI after the addition of VEE aregiven in the following Table 4. After 2 hours of hydrogenation, thehydrogenation degree reached 99.8% and 99.7% respectively as shown inTable 4. The final molecular weights and the PDI are given in thefollowing Table 3.

Example 11 Comparison Example; NBR-7; Using Catalyst (2) withoutPre-Treatment

Catalyst (2) (363 mg) was dissolved in 100 g degassed MCB in a cylinder.A solution of 518 g NBR-7 dissolved in MCB (a solid concentration of 13wt % of NBR solution) was bubbled with nitrogen in a 10 L autoclave for30 minutes, and then heated to 140° C. The catalyst solution in thecylinder was pressured into the reactor with hydrogen gas. Hydrogenationwas conducted under 8.4 MPa of hydrogen pressure and 600 rpm ofagitation speed. Samples were taken from the reactor at intervals forFT-IR analysis to determine the hydrogenation degree. After 4 hours ofhydrogenation, the hydrogenation degree reached >99%. The finalmolecular weights and the PDI were: Mn=48,564, Mw=127,044, PDI=2.60.

Example 12 Inventive Example; NBR-7; Catalyst (2); VEE as Co-Catalyst

Catalyst (2) (259 mg) was dissolved in 100 g degassed MCB in a cylinder.Vinyl ethyl ether (1.41 g) was injected into the cylinder and thesolution was stirred at room temperature for 1 hour. A solution of 518 gNBR-7 dissolved in MCB (a solid concentration of 13 wt % of NBRsolution) was bubbled with nitrogen in a 10 L autoclave for 30 minutes,and then heated to 140° C. The pre-treated catalyst solution in thecylinder was pressured into the reactor with hydrogen gas. Hydrogenationwas conducted under 8.4 Mpa of hydrogen pressure and 600 rpm ofagitation speed. Samples were taken from the reactor at intervals forFT-IR analysis to determine the hydrogenation degree. After 4 hours ofhydrogenation, the hydrogenation degree reached >99%. The finalmolecular weights and the PDI were: Mn=82,973, Mw=261,751, PDI=3.20.

The examples in this section show that HNBR can be prepared byhydrogenation of NBR in the presence of a catalyst composition which isobtained by contacting a metathesis catalyst with a specific co-catalystwherein such contacting or pretreatment of the catalyst with theco-catalyst is conducted either separately (see Ex. 2-5 and Ex. 7) orfollowing a metathesis reaction in-situ in the reaction mixture beforethe addition of hydrogen (see Ex. 8 to 10). The metathesis activity ofthe catalyst is controlled by contacting the catalyst with theco-catalyst and thereby preparing the catalyst composition according tothe invention. Thus the molecular weight of the HNBR obtained by thehydrogenation using the catalyst composition according to the inventionis comparable to the original NBR feedstock. This is clearly shown e.g.by Ex. 7 in which 1-hexene which is known as typical co-olefine toenhance metathesis reactions was added to the hydrogenation reaction,but nevertheless no methathesis occurred and the average molecularweights Mn and Mw of the HNBR obtained are nearly identical to therespective values of the starting NBR. Further, the non-inventive Ex.11* and the inventive Ex. 12 show that, with the catalyst compositionwhich is obtained by contacting a metathesis catalyst with a specificco-catalyst, the same hydrogenation rate can be achieved by using lowerloading of the metathesis catalyst (Ex. 12: 259 mg Grubbs II catalystvs. Ex 11*: 363 mg Grubbs II catalyst). Therefore, besides controllingthe metathesis activity of the metathesis catalyst, it is surprisinglyfound that, by using such catalyst composition, the hydrogenationactivity of the catalyst also be promoted/improved.

TABLE 3 Reaction conditions and results of Examples 6 to 10 (1-hexene asco-catalyst for metathesis: 4.0 phr, hydrogenation pressure: 8.4 MPa,hydrogenation temperature: 140° C., hydrogenation time: 2 h) MCB tosolve NBR, Molar catalyst Step 1: Co-catalyst for ratio NBR andco-catalyst Catalyst (2) Metathesis pretreating the catalyst co-catalystamount amount amount time amount to Ex [g] [g] [mg] [mmol] [h] type [g][mmol] catalyst  6* 270 4500 135 0.1590 1   — — — — NBR-5 7 270 4500 1350.1590 — VEE 0.75 10.34 65 NBR-6 8 560 4666 280 0.3298 0.25 VEE 1.5521.49 65 NBR-6 9 560 4666 280 0.3298 0.25 VEE 2.38 33.01 100  NBR-6 10 560 4666 280 0.3298 0.25 VEE 0.95 13.17 40 NBR-6 11* 518 3567 363 0 4276— — — — — NBR-7 12  518 3567 259 0.3051 — — — — 64 NBR-7 PretreatmentCatalyst Hydrogenation time Mn Mw degree Ex [h] [g/mol] [g/mol] PDI [%]HNBR  6* — after metathesis 14,360 34,287 2.39 0 after hydrogenation4,648 9,952 2.14 99.5 7 12  after hydrogenation 74,698 258,405 2.79 99.48 1 after metathesis and 54,576 147,365 2 70 0 VEE addition afterhydrogenation 61,976 168,310 2.72 99.8 9 1 after metathesis and 56,499138,269 2 45 0 VEE addition after hydrogenation 62,402 155,444 2.49 99.710  1 after metathesis and 56,127 137,659 2 45 0 VEE addition afterhydrogenation 64,608 163,139 2.52 99.7 11* — after hydrogenation 48,564127,044 2.60 >99 12  1 after hydrogenation 82,973 261,751 3.20 >99 NBRNBR-5 73,711 243,671 3.31 NBR-6 74,698 249,935 3.35 NBR-7 70,674 251,2923.56

What is claimed is:
 1. A catalyst composition obtainable by contacting acomplex catalyst based on ruthenium or osmium as central metal andbearing at least one ligand which is bound to the ruthenium or osmiumcentral metal in a carbene-like fashion with at least one co-catalyst ina molar ratio of the complex catalyst to the co-catalyst in a range offrom 1:(20-550) wherein the co-catalyst must contain at least one vinylgroup.
 2. The catalyst composition according to claim 1 wherein theco-catalyst has the general formula (1)CH₂═CRR′  (1) in which R and R′ are identical or different and shallmean hydrogen or OR¹ wherein R¹ shall mean alkyl, cycloalkyl, alkenyl,alkynyl, aryl, or heteroaryl, C(═O)(R²), —C(═O)N(R²)₂,—[(CH₂)_(n)—X]_(m)R², —[(CH₂)_(n)—X]_(m)—CH═CH₂, or —(CH₂)_(p)—C(R³)₂R⁴wherein X is identical or different and means oxygen (O) or NR² R² areidentical or different and represent H, alkyl, cycloalkyl, alkenyl,alkynyl, aryl, or heteroaryl, R³ are identical or different andrepresent C₁-C₅ alkyl or —(CH₂)_(n)—O—CH═CH₂, R⁴ represents(CH₂)_(p)—O—CH═CH₂, n is in the range of from 1 to 5, m is in the rangeof from 1 to 10, p is in the range of from 0 to 5, where in thealternative, if R and R′ both represent a group OR¹, both R¹ may belinked to each other and together represent a divalent group—(C(R²)₂)_(q)— with q being 2, 3 or 4 and R² being identical ordifferent and having the above defined meanings, or SR⁵, SOR⁵, SO₂R⁵wherein R⁵ represents alkyl, cycloalkyl, alkenyl, alkynyl, aryl, orheteroaryl, or N(R⁶R⁷), P(R⁶R⁷) wherein R⁶ and R⁷ are identical ordifferent and shall mean alkyl, cycloalkyl, alkenyl, alkynyl, aryl,heteroaryl, —C(═O)(R²), or where in the alternative R⁶ and R⁷ may formtogether with such N or P atom to which they both are linked at the sametime a saturated, unsaturated or aromatic cyclic structure with 4 to 7carbon atoms in the cyclic structure wherein one, two or three of saidcarbon atoms can be replaced by a moiety selected from oxygen, sulfur,nitrogen, N—R⁸ or P—R⁸ wherein R⁸ shall mean alkyl, cycloalkyl, alkenyl,alkynyl, aryl, or heteroaryl; or P(═O)(OR⁹)₂ in which R⁹ are identicalor different and shall mean alkyl, cycloalkyl, alkenyl, alkynyl, aryl,heteroaryl, however, under the proviso that R and R′ must not bothrepresent hydrogen in formula (1) at the same time.
 3. The catalystcomposition according to claim 1 wherein the co-catalyst is selectedfrom the group consisting of formulae (cocat-1) to (cocat-38).


4. The catalyst composition according to any one claims 1 to 3 whereinthe complex catalyst is selected from the group consisting of (i)catalysts of general formula (A),

where M is osmium or ruthenium, X¹ and X² are identical or different andare two ligands, preferably anionic ligands, L are identical ordifferent ligands, preferably uncharged electron donors, R are identicalor different and are each hydrogen, alkyl, preferably C₁-C₃₀-alkyl,cycloalkyl, preferably C₃-C₂₀-cycloalkyl, alkenyl, preferablyC₂-C₂₀-alkenyl, alkynyl, preferably C₂-C₂₀-alkynyl, aryl, preferablyC₆-C₂₄-aryl, carboxylate, preferably C₁-C₂₀-carboxylate, alkoxy,preferably C₁-C₂₀-alkoxy, alkenyloxy, preferably C₂-C₂₀-alkenyloxy,alkynyloxy, preferably C₂-C₂₀-alkynyloxy, aryloxy, preferablyC₆-C₂₄-aryloxy, alkoxycarbonyl, preferably C₂-C₂₀-alkoxycarbonyl,alkylamino, preferably C₁-C₃₀-alkylamino, alkylthio, preferablyC₁-C₃₀-alkylthio, arylthio, preferably C₆-C₂₄-arylthio, alkylsulphonyl,preferably C₁-C₂₀-alkylsulphonyl, or alkylsulphinyl, preferablyC₁-C₂₀-alkylsulphinyl, where these groups may in each case optionally besubstituted by one or more alkyl, halogen, alkoxy, aryl or heteroarylmoities or, as an alternative, the two groups R together with the commoncarbon atom to which they are bound are bridged to form a cyclicstructure which can be aliphatic or aromatic in nature, may besubstituted and may contain one or more heteroatoms, (ii) catalysts ofgeneral formula (A1),

where X¹, X² and L can have the same general, preferred and particularlypreferred meanings as in the general formula (A), n is 0, 1 or 2, m is0, 1, 2, 3 or 4 and R′ are identical or different and are alkyl,cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy,aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonylor alkylsulphinyl radicals which may in each case be substituted by oneor more alkyl, halogen, alkoxy, aryl or heteroaryl, (iii) catalysts ofgeneral formula (B),

where M is ruthenium or osmium, X¹ and X² are identical or different andare anionic ligands, R″ are identical or different and are organicmoieties, Im is a substituted or unsubstituted imidazoline orimidazolidine ligand and An is an anion, (iv) catalysts of generalformula (C)

where M is ruthenium or osmium, R¹³ and R¹⁴ are each, independently ofone another, hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl,C₆-C₂₄-aryl, C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy,C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl,C₁-C₂₀-alkylthio, C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl, X³ isan anionic ligand, L² is an uncharged π-bonded ligand which may eitherbe monocyclic or polycyclic, L³ is a ligand selected from the groupconsisting of phosphines, sulphonated phosphines, fluorinatedphosphines, functionalized phosphines having up to three aminoalkyl,ammonioalkyl, alkoxyalkyl, alkoxycarbonylalkyl, hydrocarbonylalkyl,hydroxyalkyl or ketoalkyl groups, phosphites, phosphinites,phosphonites, phosphinamines, arsines stibines, ethers, amines, amides,imines, sulphoxides, thioethers and pyridines, Y⁻ is a noncoordinatinganion and n is 0, 1, 2, 3, 4 or 5, (v) catalysts of general formula (D),

where M is ruthenium or osmium, X¹ and X² are identical or different andare anionic ligands which can have all meanings of X¹ and X² mentionedin the general formulae (A) and (B), L represent identical or differentligands which can have all general and preferred meanings of L mentionedin the general formulae (A) and (B), R¹⁹ and R²⁰ are identical ordifferent and are each hydrogen or substituted or unsubstituted alkyl,(vi) catalysts of general formula (E), (F) or (G),

where M is osmium or ruthenium, X¹ and X² are identical or different andare two ligands, preferably anionic ligands, L is a ligand, preferablyan uncharged electron donor, Z¹ and Z²are identical or different and areuncharged electron donors, R²¹ and R²² are each, independently of oneanother, hydrogen alkyl, cycloalkyl, alkenyl, alkynyl, aryl,carboxylate, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl,alkylamino, alkylthio, alkylsulphonyl or alkylsulphinyl which are ineach case substituted by one or more substituents selected from amongalkyl, halogen, alkoxy, aryl or heteroaryl. (vii) catalysts (N)comprising the general structural element (N1), where the carbon atomdenoted by “*” is bound via one or more double bonds to the catalystframework having a ruthenium or osmium central metal,

and where R²⁵-R³² are identical or different and are each hydrogen,halogen, hydroxyl, aldehyde, keto, thiol, CF₃, nitro, nitroso, cyano,thiocyano, isocyanato, carbodiimide, carbamate, thiocarbamate,dithiocarbamate, amino, amido, imino, silyl, sulphonate (—SO₃ ⁻), —OSO₃⁻, —PO₃ ⁻ or OPO₃ ⁻ or alkyl, cycloalkyl, alkenyl, alkynyl, aryl,carboxylate, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl,alkylamino, alkylthio, arylthio, alkylsulphonyl, alkylsulphinyl,dialkylamino, alkylsilyl or alkoxysilyl, where all these moieties caneach optionally be substituted by one or more alkyl, halogen, alkoxy,aryl or heteroaryl substituents, or, as an alternative, two directlyadjacent substituents from the group consisting of R²⁵-R³² together withthe ring carbons to which they are bound form a cyclic group, preferablyan aromatic system, by bridging or, as an alternative, R⁸ is optionallybridged to another ligand of the ruthenium- or osmium-carbene complexcatalyst, m is 0 or 1 and A is oxygen, sulphur, C(R³³R³⁴), N—R³⁵,—C(R³⁶)═C(R³⁷)—, —C(R³⁶)(R³⁸)—C(R³⁷)(R³⁹)—, where R³³-R³⁹ are identicalor different and can each have the same meanings as R²⁵-R³², and (viii)catalysts of general formulae (N2a) or (N2b),

where M is ruthenium or osmium, X¹ and X² are identical or different andare two ligands, preferably anionic ligands, L¹ and L² are identical ordifferent ligands, preferably uncharged electron donors, where L² canalternatively also be bridged to the radical R⁸, n is 0, 1, 2 or 3,preferably 0, 1 or 2, n′ is 1 or 2, preferably 1, and R²⁵-R³², m and Ahave the same meanings as given in general formula (N1).
 5. The catalystcomposition according to claim 4 wherein a complex catalyst of generalformula (A) is used in which one group R is hydrogen and the other groupR is C₁-C₂₀-alkyl, C₃-C₁₀-cycloalkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl,C₆-C₂₄-aryl, C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy,C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl,C₁-C₃₀-alkylamino, C₁-C₃₀-alkylthio, C₆-C₂₄-arylthio,C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl, where these moieties mayin each case be substituted by one or more alkyl, halogen, alkoxy, arylor heteroaryl groups.
 6. The catalyst composition according to claim 4or 5 wherein a complex catalyst of general formula (A) is used in whichX¹ and X² are identical and are each halogen, in particular chlorine,CF₃COO, CH₃COO, CFH₂COO, (CH₃)₃CO, (CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO, PhO(phenoxy), MeO (methoxy), EtO (ethoxy), tosylate (p-CH₃—C₆H₄—SO₃),mesylate (CH₃—SO₃) or CF₃SO₃ (trifluoromethanesulphonate).
 7. Thecatalyst composition according to any one of claims 4 to 6 wherein acomplex catalyst of general formula (A) is used in which one or both ofthe ligands L have a structure according to general formulae(IIa)-(IId), wherein the meaning of L can be identical or different incase both ligands L have a structure according to (IIa) to (IId),

where R⁸, R⁹, R¹⁰ and R¹¹ are identical or different and representhydrogen, straight-chain or branched C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl,C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₇-C₂₅-alkaryl, C₂-C₂₀heteroaryl, C₂-C₂₀ heterocyclyl, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy,C₂-C₂₀-alkynyloxy, C₆-C₂₀-aryloxy, C₂-C₂₀-alkoxycarbonyl,C₁-C₂₀-alkylthio, C₆-C₂₀-arylthio, —Si(R)₃, —O—Si(R)₃, —O—C(═O)R,C(═O)R, —C(═O)N(R)₂, —NR—C(═O)—N(R)₂, —SO₂N(R)₂, —S(═O)R, —S(═O)₂R,—O—S(═O)₂R, halogen, nitro or cyano, wherein in all above occurrencesrelating to the meanings of R⁸, R⁹, R¹⁰ and R¹¹ the group R is identicalor different and represents hydrogen, alkyl, cycloalkyl, alkenyl,alkynyl, aryl or heteroaryl, and R¹⁵, R¹⁶ and R¹⁷ are identical ordifferent and may represent alkyl, cycloalkyl, alkoxy, aryl, aryloxy, ora heterocyclic group.
 8. The catalyst composition according to any oneof claims 4 to 6 wherein a complex catalyst of general formula (A) isused in which one or both of the ligands L may have a structure (IIIa)to (IIIu), where in all cases “Ph” means phenyl, “Bu” butyl, “Mes”2,4,6-trimethylphenyl, “Dipp” 2,6-diisopropylphenyl, and “Dimp”2,6-dimethylphenyl, and wherein the meaning of L can be identical ordifferent in case both ligands L have a structure according to (IIIa) to(IIIu),


9. The catalyst composition according to any one of claims 4 to 8wherein in step a) a catalyst of general formula (A) is used inimmobilized form on a support material, preferably as immobilizedcatalyst having the general formulae (support-1), (support-2), or(support-3),

wherein M, Y, L, X¹, X², and R may have the meanings given for generalformula (A) and wherein “supp” stands for the support material,preferably silica gels or a macromolecular material, more preferablysynthetic polymers, most preferably polyethylene glycol, polystyrenes orcross-linked polystyrenes.
 10. The catalyst composition according toclaim 4 wherein in step a) a catalyst of the general formulae (E), (F),and (G) is used in which M is ruthenium, X¹ and X² are both halogen, inparticular chlorine, R¹ and R² are identical or different and are five-or six-membered monocyclic groups having from 1 to 4, preferably from 1to 3 and particularly preferably 1 or 2, heteroatoms or bicyclic orpolycyclic structures made up of 2, 3, 4 or 5 five- or six-memberedmonocyclic groups of this type, where all the abovementioned groups mayin each case be substituted by one or more moieties selected from thegroup consisting of alkyl, preferably C₁-C₁₀-alkyl, cycloalkyl,preferably C₃-C₈-cycloalkyl, alkoxy, preferably C₁-C₁₀-alkoxy, halogen,preferably chlorine or bromine, aryl, preferably C₆-C₂₄-aryl, orheteroaryl, preferably C₅-C₂₃-heteroaryl, Z¹ and Z² are identical ordifferent and five- or six-membered monocyclic groups having from 1 to4, preferably from 1 to 3 and particularly preferably 1 or 2,heteroatoms or bicyclic or polycyclic structures made up of 2, 3, 4 or 5five- or six-membered monocyclic groups of this type, where all theseabovementioned groups may in each case optionally be substituted by oneor more alkyl, preferably C₁-C₁₀-alkyl, cycloalkyl, preferablyC₃-C₈-cycloalkyl, alkoxy, preferably C₁-C₁₀-alkoxy, halogen, preferablychlorine or bromine, aryl, preferably C₆-C₂₄-aryl, or heteroaryl,preferably C₅-C₂₃-heteroaryl, radicals which may in turn each besubstituted by one or more moieties, preferably selected from the groupconsisting of halogen, in particular chlorine or bromine, C₁-C₅-alkyl,C₁-C₅-alkoxy and phenyl. R²¹ and R²² are identical or different and areeach C₁-C₃₀-alkyl C₃-C₂₀-cycloalkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl,C₆-C₂₄-aryl, C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy,C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl,C₁-C₃₀-alkylamino, C₁-C₃₀-alkylthio, C₆-C₂₄-arylthio,C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphinyl, and L has a structure ofthe above-described general formula (IIa) or (IIb), in particular one ofthe formulae (IIIa) to (IIIu).
 11. The catalyst composition according toany one of claims 1 to 3, wherein in step a) a complex catalyst is usedselected from the catalysts shown in the following formulae, wherein ineach case “Cy” is cyclohexyl, “Mes” is 2,4,6-trimethylphenyl and “Ph” isphenyl.


12. The catalyst composition according to any one of claims 1 to 11wherein the molar ratio of of the complex catalyst to the co-catalyst ina range of from 1:(20 to below 100), preferably 1:(25 to 99.5), morepreferably 1:(30 to 99), even more preferably 1:(35 to 98.5) and mostpreferably 1:(40 to 70).
 13. A process for hydrogenating a nitrilerubber comprising a) preparing the catalyst composition by contacting acomplex catalyst based on ruthenium or osmium as central metal andbearing at least one ligand which is bound to the ruthenium or osmiumcentral metal in a carbene-like fashion with at least one co-catalyst ina molar ratio of the complex catalyst to the co-catalyst in the range of1:(20-550) wherein the co-catalyst must contain at least one vinyl groupand thereafter b) hydrogenating the nitrile rubber in the presence ofthe catalyst composition formed in step a).
 14. The process forhydrogenating a nitrile rubber according to claim 13, wherein step a) isperformed at a temperature in the range of from −20° C. to 160° C. andpreferably in the range of from 20° C. to 80° C.
 15. The process forhydrogenating a nitrile rubber according to claim 13 or 14, wherein theratio of complex catalyst to co-catalyst in step a) is 1:(20-500),preferably 1:(25-475), more preferably 1:(25-450) and most preferably1:(30-450).
 16. The process for hydrogenating a nitrile rubber accordingto claim 13 or 14, wherein the molar ratio of of the complex catalyst tothe co-catalyst in a range of from 1:(20 to below 100), preferably 1:(25to 99.5), more preferably 1:(30 to 99), even more preferably 1:(35 to98.5) and most preferably 1:(40 to 70).
 17. The process forhydrogenating a nitrile rubber according to any one of claims 13 to 16,wherein the hydrogenation in step b) is carried out at a temperature inthe range of from 60° C. to 200° C., preferably from 80° C. to 180° C.,most preferably from 100° C. to 160° C. and at a hydrogen pressure inthe range of 0.5 MPa to 35 MPa, more preferably of 3.0 MPa to 10 MPa.18. The process for preparing a hydrogenated nitrile rubber according toany one of claims 13 to 17, wherein the nitrile rubber prior to beinghydrogenated is subjected to a molecular weight degradation in ametathesis reaction first comprising contacting the said nitrile rubberin the absence or presence of a co-olefin with a complex catalyst basedon ruthenium or osmium as central metal and bearing at least one ligandwhich is bound to the ruthenium or osmium central metal in acarbene-like fashion, then c) contacting the complex catalyst which ispresent in the reaction mixture obtained after the metathesis reactionwith at least one co-catalyst having at least one vinyl group in a molarratio of the complex catalyst to the co-catalyst in the range of1:(20-550) to form a catalyst composition and thereafter d)hydrogenating the nitrile rubber in the presence of the catalystcomposition.